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llvm-6502/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
Duncan Sands 28b77e968d Add codegen support for vector select (in the IR this means a select 
with a vector condition); such selects become VSELECT codegen nodes.
This patch also removes VSETCC codegen nodes, unifying them with SETCC
nodes (codegen was actually often using SETCC for vector SETCC already).
This ensures that various DAG combiner optimizations kick in for vector
comparisons.  Passes dragonegg bootstrap with no testsuite regressions
(nightly testsuite as well as "make check-all").  Patch mostly by
Nadav Rotem.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139159 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-06 19:07:46 +00:00

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//===-- DAGCombiner.cpp - Implement a DAG node combiner -------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This pass combines dag nodes to form fewer, simpler DAG nodes. It can be run
// both before and after the DAG is legalized.
//
// This pass is not a substitute for the LLVM IR instcombine pass. This pass is
// primarily intended to handle simplification opportunities that are implicit
// in the LLVM IR and exposed by the various codegen lowering phases.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "dagcombine"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/DerivedTypes.h"
#include "llvm/LLVMContext.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/PseudoSourceValue.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
using namespace llvm;
STATISTIC(NodesCombined , "Number of dag nodes combined");
STATISTIC(PreIndexedNodes , "Number of pre-indexed nodes created");
STATISTIC(PostIndexedNodes, "Number of post-indexed nodes created");
STATISTIC(OpsNarrowed , "Number of load/op/store narrowed");
STATISTIC(LdStFP2Int , "Number of fp load/store pairs transformed to int");
namespace {
static cl::opt<bool>
CombinerAA("combiner-alias-analysis", cl::Hidden,
cl::desc("Turn on alias analysis during testing"));
static cl::opt<bool>
CombinerGlobalAA("combiner-global-alias-analysis", cl::Hidden,
cl::desc("Include global information in alias analysis"));
//------------------------------ DAGCombiner ---------------------------------//
class DAGCombiner {
SelectionDAG &DAG;
const TargetLowering &TLI;
CombineLevel Level;
CodeGenOpt::Level OptLevel;
bool LegalOperations;
bool LegalTypes;
// Worklist of all of the nodes that need to be simplified.
std::vector<SDNode*> WorkList;
// AA - Used for DAG load/store alias analysis.
AliasAnalysis &AA;
/// AddUsersToWorkList - When an instruction is simplified, add all users of
/// the instruction to the work lists because they might get more simplified
/// now.
///
void AddUsersToWorkList(SDNode *N) {
for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end();
UI != UE; ++UI)
AddToWorkList(*UI);
}
/// visit - call the node-specific routine that knows how to fold each
/// particular type of node.
SDValue visit(SDNode *N);
public:
/// AddToWorkList - Add to the work list making sure it's instance is at the
/// the back (next to be processed.)
void AddToWorkList(SDNode *N) {
removeFromWorkList(N);
WorkList.push_back(N);
}
/// removeFromWorkList - remove all instances of N from the worklist.
///
void removeFromWorkList(SDNode *N) {
WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), N),
WorkList.end());
}
SDValue CombineTo(SDNode *N, const SDValue *To, unsigned NumTo,
bool AddTo = true);
SDValue CombineTo(SDNode *N, SDValue Res, bool AddTo = true) {
return CombineTo(N, &Res, 1, AddTo);
}
SDValue CombineTo(SDNode *N, SDValue Res0, SDValue Res1,
bool AddTo = true) {
SDValue To[] = { Res0, Res1 };
return CombineTo(N, To, 2, AddTo);
}
void CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO);
private:
/// SimplifyDemandedBits - Check the specified integer node value to see if
/// it can be simplified or if things it uses can be simplified by bit
/// propagation. If so, return true.
bool SimplifyDemandedBits(SDValue Op) {
unsigned BitWidth = Op.getValueType().getScalarType().getSizeInBits();
APInt Demanded = APInt::getAllOnesValue(BitWidth);
return SimplifyDemandedBits(Op, Demanded);
}
bool SimplifyDemandedBits(SDValue Op, const APInt &Demanded);
bool CombineToPreIndexedLoadStore(SDNode *N);
bool CombineToPostIndexedLoadStore(SDNode *N);
void ReplaceLoadWithPromotedLoad(SDNode *Load, SDNode *ExtLoad);
SDValue PromoteOperand(SDValue Op, EVT PVT, bool &Replace);
SDValue SExtPromoteOperand(SDValue Op, EVT PVT);
SDValue ZExtPromoteOperand(SDValue Op, EVT PVT);
SDValue PromoteIntBinOp(SDValue Op);
SDValue PromoteIntShiftOp(SDValue Op);
SDValue PromoteExtend(SDValue Op);
bool PromoteLoad(SDValue Op);
void ExtendSetCCUses(SmallVector<SDNode*, 4> SetCCs,
SDValue Trunc, SDValue ExtLoad, DebugLoc DL,
ISD::NodeType ExtType);
/// combine - call the node-specific routine that knows how to fold each
/// particular type of node. If that doesn't do anything, try the
/// target-specific DAG combines.
SDValue combine(SDNode *N);
// Visitation implementation - Implement dag node combining for different
// node types. The semantics are as follows:
// Return Value:
// SDValue.getNode() == 0 - No change was made
// SDValue.getNode() == N - N was replaced, is dead and has been handled.
// otherwise - N should be replaced by the returned Operand.
//
SDValue visitTokenFactor(SDNode *N);
SDValue visitMERGE_VALUES(SDNode *N);
SDValue visitADD(SDNode *N);
SDValue visitSUB(SDNode *N);
SDValue visitADDC(SDNode *N);
SDValue visitADDE(SDNode *N);
SDValue visitMUL(SDNode *N);
SDValue visitSDIV(SDNode *N);
SDValue visitUDIV(SDNode *N);
SDValue visitSREM(SDNode *N);
SDValue visitUREM(SDNode *N);
SDValue visitMULHU(SDNode *N);
SDValue visitMULHS(SDNode *N);
SDValue visitSMUL_LOHI(SDNode *N);
SDValue visitUMUL_LOHI(SDNode *N);
SDValue visitSMULO(SDNode *N);
SDValue visitUMULO(SDNode *N);
SDValue visitSDIVREM(SDNode *N);
SDValue visitUDIVREM(SDNode *N);
SDValue visitAND(SDNode *N);
SDValue visitOR(SDNode *N);
SDValue visitXOR(SDNode *N);
SDValue SimplifyVBinOp(SDNode *N);
SDValue visitSHL(SDNode *N);
SDValue visitSRA(SDNode *N);
SDValue visitSRL(SDNode *N);
SDValue visitCTLZ(SDNode *N);
SDValue visitCTTZ(SDNode *N);
SDValue visitCTPOP(SDNode *N);
SDValue visitSELECT(SDNode *N);
SDValue visitSELECT_CC(SDNode *N);
SDValue visitSETCC(SDNode *N);
SDValue visitSIGN_EXTEND(SDNode *N);
SDValue visitZERO_EXTEND(SDNode *N);
SDValue visitANY_EXTEND(SDNode *N);
SDValue visitSIGN_EXTEND_INREG(SDNode *N);
SDValue visitTRUNCATE(SDNode *N);
SDValue visitBITCAST(SDNode *N);
SDValue visitBUILD_PAIR(SDNode *N);
SDValue visitFADD(SDNode *N);
SDValue visitFSUB(SDNode *N);
SDValue visitFMUL(SDNode *N);
SDValue visitFDIV(SDNode *N);
SDValue visitFREM(SDNode *N);
SDValue visitFCOPYSIGN(SDNode *N);
SDValue visitSINT_TO_FP(SDNode *N);
SDValue visitUINT_TO_FP(SDNode *N);
SDValue visitFP_TO_SINT(SDNode *N);
SDValue visitFP_TO_UINT(SDNode *N);
SDValue visitFP_ROUND(SDNode *N);
SDValue visitFP_ROUND_INREG(SDNode *N);
SDValue visitFP_EXTEND(SDNode *N);
SDValue visitFNEG(SDNode *N);
SDValue visitFABS(SDNode *N);
SDValue visitBRCOND(SDNode *N);
SDValue visitBR_CC(SDNode *N);
SDValue visitLOAD(SDNode *N);
SDValue visitSTORE(SDNode *N);
SDValue visitINSERT_VECTOR_ELT(SDNode *N);
SDValue visitEXTRACT_VECTOR_ELT(SDNode *N);
SDValue visitBUILD_VECTOR(SDNode *N);
SDValue visitCONCAT_VECTORS(SDNode *N);
SDValue visitVECTOR_SHUFFLE(SDNode *N);
SDValue visitMEMBARRIER(SDNode *N);
SDValue XformToShuffleWithZero(SDNode *N);
SDValue ReassociateOps(unsigned Opc, DebugLoc DL, SDValue LHS, SDValue RHS);
SDValue visitShiftByConstant(SDNode *N, unsigned Amt);
bool SimplifySelectOps(SDNode *SELECT, SDValue LHS, SDValue RHS);
SDValue SimplifyBinOpWithSameOpcodeHands(SDNode *N);
SDValue SimplifySelect(DebugLoc DL, SDValue N0, SDValue N1, SDValue N2);
SDValue SimplifySelectCC(DebugLoc DL, SDValue N0, SDValue N1, SDValue N2,
SDValue N3, ISD::CondCode CC,
bool NotExtCompare = false);
SDValue SimplifySetCC(EVT VT, SDValue N0, SDValue N1, ISD::CondCode Cond,
DebugLoc DL, bool foldBooleans = true);
SDValue SimplifyNodeWithTwoResults(SDNode *N, unsigned LoOp,
unsigned HiOp);
SDValue CombineConsecutiveLoads(SDNode *N, EVT VT);
SDValue ConstantFoldBITCASTofBUILD_VECTOR(SDNode *, EVT);
SDValue BuildSDIV(SDNode *N);
SDValue BuildUDIV(SDNode *N);
SDValue MatchBSwapHWordLow(SDNode *N, SDValue N0, SDValue N1,
bool DemandHighBits = true);
SDValue MatchBSwapHWord(SDNode *N, SDValue N0, SDValue N1);
SDNode *MatchRotate(SDValue LHS, SDValue RHS, DebugLoc DL);
SDValue ReduceLoadWidth(SDNode *N);
SDValue ReduceLoadOpStoreWidth(SDNode *N);
SDValue TransformFPLoadStorePair(SDNode *N);
SDValue GetDemandedBits(SDValue V, const APInt &Mask);
/// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes,
/// looking for aliasing nodes and adding them to the Aliases vector.
void GatherAllAliases(SDNode *N, SDValue OriginalChain,
SmallVector<SDValue, 8> &Aliases);
/// isAlias - Return true if there is any possibility that the two addresses
/// overlap.
bool isAlias(SDValue Ptr1, int64_t Size1,
const Value *SrcValue1, int SrcValueOffset1,
unsigned SrcValueAlign1,
const MDNode *TBAAInfo1,
SDValue Ptr2, int64_t Size2,
const Value *SrcValue2, int SrcValueOffset2,
unsigned SrcValueAlign2,
const MDNode *TBAAInfo2) const;
/// FindAliasInfo - Extracts the relevant alias information from the memory
/// node. Returns true if the operand was a load.
bool FindAliasInfo(SDNode *N,
SDValue &Ptr, int64_t &Size,
const Value *&SrcValue, int &SrcValueOffset,
unsigned &SrcValueAlignment,
const MDNode *&TBAAInfo) const;
/// FindBetterChain - Walk up chain skipping non-aliasing memory nodes,
/// looking for a better chain (aliasing node.)
SDValue FindBetterChain(SDNode *N, SDValue Chain);
public:
DAGCombiner(SelectionDAG &D, AliasAnalysis &A, CodeGenOpt::Level OL)
: DAG(D), TLI(D.getTargetLoweringInfo()), Level(Unrestricted),
OptLevel(OL), LegalOperations(false), LegalTypes(false), AA(A) {}
/// Run - runs the dag combiner on all nodes in the work list
void Run(CombineLevel AtLevel);
SelectionDAG &getDAG() const { return DAG; }
/// getShiftAmountTy - Returns a type large enough to hold any valid
/// shift amount - before type legalization these can be huge.
EVT getShiftAmountTy(EVT LHSTy) {
return LegalTypes ? TLI.getShiftAmountTy(LHSTy) : TLI.getPointerTy();
}
/// isTypeLegal - This method returns true if we are running before type
/// legalization or if the specified VT is legal.
bool isTypeLegal(const EVT &VT) {
if (!LegalTypes) return true;
return TLI.isTypeLegal(VT);
}
};
}
namespace {
/// WorkListRemover - This class is a DAGUpdateListener that removes any deleted
/// nodes from the worklist.
class WorkListRemover : public SelectionDAG::DAGUpdateListener {
DAGCombiner &DC;
public:
explicit WorkListRemover(DAGCombiner &dc) : DC(dc) {}
virtual void NodeDeleted(SDNode *N, SDNode *E) {
DC.removeFromWorkList(N);
}
virtual void NodeUpdated(SDNode *N) {
// Ignore updates.
}
};
}
//===----------------------------------------------------------------------===//
// TargetLowering::DAGCombinerInfo implementation
//===----------------------------------------------------------------------===//
void TargetLowering::DAGCombinerInfo::AddToWorklist(SDNode *N) {
((DAGCombiner*)DC)->AddToWorkList(N);
}
void TargetLowering::DAGCombinerInfo::RemoveFromWorklist(SDNode *N) {
((DAGCombiner*)DC)->removeFromWorkList(N);
}
SDValue TargetLowering::DAGCombinerInfo::
CombineTo(SDNode *N, const std::vector<SDValue> &To, bool AddTo) {
return ((DAGCombiner*)DC)->CombineTo(N, &To[0], To.size(), AddTo);
}
SDValue TargetLowering::DAGCombinerInfo::
CombineTo(SDNode *N, SDValue Res, bool AddTo) {
return ((DAGCombiner*)DC)->CombineTo(N, Res, AddTo);
}
SDValue TargetLowering::DAGCombinerInfo::
CombineTo(SDNode *N, SDValue Res0, SDValue Res1, bool AddTo) {
return ((DAGCombiner*)DC)->CombineTo(N, Res0, Res1, AddTo);
}
void TargetLowering::DAGCombinerInfo::
CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO) {
return ((DAGCombiner*)DC)->CommitTargetLoweringOpt(TLO);
}
//===----------------------------------------------------------------------===//
// Helper Functions
//===----------------------------------------------------------------------===//
/// isNegatibleForFree - Return 1 if we can compute the negated form of the
/// specified expression for the same cost as the expression itself, or 2 if we
/// can compute the negated form more cheaply than the expression itself.
static char isNegatibleForFree(SDValue Op, bool LegalOperations,
unsigned Depth = 0) {
// No compile time optimizations on this type.
if (Op.getValueType() == MVT::ppcf128)
return 0;
// fneg is removable even if it has multiple uses.
if (Op.getOpcode() == ISD::FNEG) return 2;
// Don't allow anything with multiple uses.
if (!Op.hasOneUse()) return 0;
// Don't recurse exponentially.
if (Depth > 6) return 0;
switch (Op.getOpcode()) {
default: return false;
case ISD::ConstantFP:
// Don't invert constant FP values after legalize. The negated constant
// isn't necessarily legal.
return LegalOperations ? 0 : 1;
case ISD::FADD:
// FIXME: determine better conditions for this xform.
if (!UnsafeFPMath) return 0;
// fold (fsub (fadd A, B)) -> (fsub (fneg A), B)
if (char V = isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1))
return V;
// fold (fneg (fadd A, B)) -> (fsub (fneg B), A)
return isNegatibleForFree(Op.getOperand(1), LegalOperations, Depth+1);
case ISD::FSUB:
// We can't turn -(A-B) into B-A when we honor signed zeros.
if (!UnsafeFPMath) return 0;
// fold (fneg (fsub A, B)) -> (fsub B, A)
return 1;
case ISD::FMUL:
case ISD::FDIV:
if (HonorSignDependentRoundingFPMath()) return 0;
// fold (fneg (fmul X, Y)) -> (fmul (fneg X), Y) or (fmul X, (fneg Y))
if (char V = isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1))
return V;
return isNegatibleForFree(Op.getOperand(1), LegalOperations, Depth+1);
case ISD::FP_EXTEND:
case ISD::FP_ROUND:
case ISD::FSIN:
return isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1);
}
}
/// GetNegatedExpression - If isNegatibleForFree returns true, this function
/// returns the newly negated expression.
static SDValue GetNegatedExpression(SDValue Op, SelectionDAG &DAG,
bool LegalOperations, unsigned Depth = 0) {
// fneg is removable even if it has multiple uses.
if (Op.getOpcode() == ISD::FNEG) return Op.getOperand(0);
// Don't allow anything with multiple uses.
assert(Op.hasOneUse() && "Unknown reuse!");
assert(Depth <= 6 && "GetNegatedExpression doesn't match isNegatibleForFree");
switch (Op.getOpcode()) {
default: llvm_unreachable("Unknown code");
case ISD::ConstantFP: {
APFloat V = cast<ConstantFPSDNode>(Op)->getValueAPF();
V.changeSign();
return DAG.getConstantFP(V, Op.getValueType());
}
case ISD::FADD:
// FIXME: determine better conditions for this xform.
assert(UnsafeFPMath);
// fold (fneg (fadd A, B)) -> (fsub (fneg A), B)
if (isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1))
return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(),
GetNegatedExpression(Op.getOperand(0), DAG,
LegalOperations, Depth+1),
Op.getOperand(1));
// fold (fneg (fadd A, B)) -> (fsub (fneg B), A)
return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(),
GetNegatedExpression(Op.getOperand(1), DAG,
LegalOperations, Depth+1),
Op.getOperand(0));
case ISD::FSUB:
// We can't turn -(A-B) into B-A when we honor signed zeros.
assert(UnsafeFPMath);
// fold (fneg (fsub 0, B)) -> B
if (ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(Op.getOperand(0)))
if (N0CFP->getValueAPF().isZero())
return Op.getOperand(1);
// fold (fneg (fsub A, B)) -> (fsub B, A)
return DAG.getNode(ISD::FSUB, Op.getDebugLoc(), Op.getValueType(),
Op.getOperand(1), Op.getOperand(0));
case ISD::FMUL:
case ISD::FDIV:
assert(!HonorSignDependentRoundingFPMath());
// fold (fneg (fmul X, Y)) -> (fmul (fneg X), Y)
if (isNegatibleForFree(Op.getOperand(0), LegalOperations, Depth+1))
return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(),
GetNegatedExpression(Op.getOperand(0), DAG,
LegalOperations, Depth+1),
Op.getOperand(1));
// fold (fneg (fmul X, Y)) -> (fmul X, (fneg Y))
return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(),
Op.getOperand(0),
GetNegatedExpression(Op.getOperand(1), DAG,
LegalOperations, Depth+1));
case ISD::FP_EXTEND:
case ISD::FSIN:
return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), Op.getValueType(),
GetNegatedExpression(Op.getOperand(0), DAG,
LegalOperations, Depth+1));
case ISD::FP_ROUND:
return DAG.getNode(ISD::FP_ROUND, Op.getDebugLoc(), Op.getValueType(),
GetNegatedExpression(Op.getOperand(0), DAG,
LegalOperations, Depth+1),
Op.getOperand(1));
}
}
// isSetCCEquivalent - Return true if this node is a setcc, or is a select_cc
// that selects between the values 1 and 0, making it equivalent to a setcc.
// Also, set the incoming LHS, RHS, and CC references to the appropriate
// nodes based on the type of node we are checking. This simplifies life a
// bit for the callers.
static bool isSetCCEquivalent(SDValue N, SDValue &LHS, SDValue &RHS,
SDValue &CC) {
if (N.getOpcode() == ISD::SETCC) {
LHS = N.getOperand(0);
RHS = N.getOperand(1);
CC = N.getOperand(2);
return true;
}
if (N.getOpcode() == ISD::SELECT_CC &&
N.getOperand(2).getOpcode() == ISD::Constant &&
N.getOperand(3).getOpcode() == ISD::Constant &&
cast<ConstantSDNode>(N.getOperand(2))->getAPIntValue() == 1 &&
cast<ConstantSDNode>(N.getOperand(3))->isNullValue()) {
LHS = N.getOperand(0);
RHS = N.getOperand(1);
CC = N.getOperand(4);
return true;
}
return false;
}
// isOneUseSetCC - Return true if this is a SetCC-equivalent operation with only
// one use. If this is true, it allows the users to invert the operation for
// free when it is profitable to do so.
static bool isOneUseSetCC(SDValue N) {
SDValue N0, N1, N2;
if (isSetCCEquivalent(N, N0, N1, N2) && N.getNode()->hasOneUse())
return true;
return false;
}
SDValue DAGCombiner::ReassociateOps(unsigned Opc, DebugLoc DL,
SDValue N0, SDValue N1) {
EVT VT = N0.getValueType();
if (N0.getOpcode() == Opc && isa<ConstantSDNode>(N0.getOperand(1))) {
if (isa<ConstantSDNode>(N1)) {
// reassoc. (op (op x, c1), c2) -> (op x, (op c1, c2))
SDValue OpNode =
DAG.FoldConstantArithmetic(Opc, VT,
cast<ConstantSDNode>(N0.getOperand(1)),
cast<ConstantSDNode>(N1));
return DAG.getNode(Opc, DL, VT, N0.getOperand(0), OpNode);
}
if (N0.hasOneUse()) {
// reassoc. (op (op x, c1), y) -> (op (op x, y), c1) iff x+c1 has one use
SDValue OpNode = DAG.getNode(Opc, N0.getDebugLoc(), VT,
N0.getOperand(0), N1);
AddToWorkList(OpNode.getNode());
return DAG.getNode(Opc, DL, VT, OpNode, N0.getOperand(1));
}
}
if (N1.getOpcode() == Opc && isa<ConstantSDNode>(N1.getOperand(1))) {
if (isa<ConstantSDNode>(N0)) {
// reassoc. (op c2, (op x, c1)) -> (op x, (op c1, c2))
SDValue OpNode =
DAG.FoldConstantArithmetic(Opc, VT,
cast<ConstantSDNode>(N1.getOperand(1)),
cast<ConstantSDNode>(N0));
return DAG.getNode(Opc, DL, VT, N1.getOperand(0), OpNode);
}
if (N1.hasOneUse()) {
// reassoc. (op y, (op x, c1)) -> (op (op x, y), c1) iff x+c1 has one use
SDValue OpNode = DAG.getNode(Opc, N0.getDebugLoc(), VT,
N1.getOperand(0), N0);
AddToWorkList(OpNode.getNode());
return DAG.getNode(Opc, DL, VT, OpNode, N1.getOperand(1));
}
}
return SDValue();
}
SDValue DAGCombiner::CombineTo(SDNode *N, const SDValue *To, unsigned NumTo,
bool AddTo) {
assert(N->getNumValues() == NumTo && "Broken CombineTo call!");
++NodesCombined;
DEBUG(dbgs() << "\nReplacing.1 ";
N->dump(&DAG);
dbgs() << "\nWith: ";
To[0].getNode()->dump(&DAG);
dbgs() << " and " << NumTo-1 << " other values\n";
for (unsigned i = 0, e = NumTo; i != e; ++i)
assert((!To[i].getNode() ||
N->getValueType(i) == To[i].getValueType()) &&
"Cannot combine value to value of different type!"));
WorkListRemover DeadNodes(*this);
DAG.ReplaceAllUsesWith(N, To, &DeadNodes);
if (AddTo) {
// Push the new nodes and any users onto the worklist
for (unsigned i = 0, e = NumTo; i != e; ++i) {
if (To[i].getNode()) {
AddToWorkList(To[i].getNode());
AddUsersToWorkList(To[i].getNode());
}
}
}
// Finally, if the node is now dead, remove it from the graph. The node
// may not be dead if the replacement process recursively simplified to
// something else needing this node.
if (N->use_empty()) {
// Nodes can be reintroduced into the worklist. Make sure we do not
// process a node that has been replaced.
removeFromWorkList(N);
// Finally, since the node is now dead, remove it from the graph.
DAG.DeleteNode(N);
}
return SDValue(N, 0);
}
void DAGCombiner::
CommitTargetLoweringOpt(const TargetLowering::TargetLoweringOpt &TLO) {
// Replace all uses. If any nodes become isomorphic to other nodes and
// are deleted, make sure to remove them from our worklist.
WorkListRemover DeadNodes(*this);
DAG.ReplaceAllUsesOfValueWith(TLO.Old, TLO.New, &DeadNodes);
// Push the new node and any (possibly new) users onto the worklist.
AddToWorkList(TLO.New.getNode());
AddUsersToWorkList(TLO.New.getNode());
// Finally, if the node is now dead, remove it from the graph. The node
// may not be dead if the replacement process recursively simplified to
// something else needing this node.
if (TLO.Old.getNode()->use_empty()) {
removeFromWorkList(TLO.Old.getNode());
// If the operands of this node are only used by the node, they will now
// be dead. Make sure to visit them first to delete dead nodes early.
for (unsigned i = 0, e = TLO.Old.getNode()->getNumOperands(); i != e; ++i)
if (TLO.Old.getNode()->getOperand(i).getNode()->hasOneUse())
AddToWorkList(TLO.Old.getNode()->getOperand(i).getNode());
DAG.DeleteNode(TLO.Old.getNode());
}
}
/// SimplifyDemandedBits - Check the specified integer node value to see if
/// it can be simplified or if things it uses can be simplified by bit
/// propagation. If so, return true.
bool DAGCombiner::SimplifyDemandedBits(SDValue Op, const APInt &Demanded) {
TargetLowering::TargetLoweringOpt TLO(DAG, LegalTypes, LegalOperations);
APInt KnownZero, KnownOne;
if (!TLI.SimplifyDemandedBits(Op, Demanded, KnownZero, KnownOne, TLO))
return false;
// Revisit the node.
AddToWorkList(Op.getNode());
// Replace the old value with the new one.
++NodesCombined;
DEBUG(dbgs() << "\nReplacing.2 ";
TLO.Old.getNode()->dump(&DAG);
dbgs() << "\nWith: ";
TLO.New.getNode()->dump(&DAG);
dbgs() << '\n');
CommitTargetLoweringOpt(TLO);
return true;
}
void DAGCombiner::ReplaceLoadWithPromotedLoad(SDNode *Load, SDNode *ExtLoad) {
DebugLoc dl = Load->getDebugLoc();
EVT VT = Load->getValueType(0);
SDValue Trunc = DAG.getNode(ISD::TRUNCATE, dl, VT, SDValue(ExtLoad, 0));
DEBUG(dbgs() << "\nReplacing.9 ";
Load->dump(&DAG);
dbgs() << "\nWith: ";
Trunc.getNode()->dump(&DAG);
dbgs() << '\n');
WorkListRemover DeadNodes(*this);
DAG.ReplaceAllUsesOfValueWith(SDValue(Load, 0), Trunc, &DeadNodes);
DAG.ReplaceAllUsesOfValueWith(SDValue(Load, 1), SDValue(ExtLoad, 1),
&DeadNodes);
removeFromWorkList(Load);
DAG.DeleteNode(Load);
AddToWorkList(Trunc.getNode());
}
SDValue DAGCombiner::PromoteOperand(SDValue Op, EVT PVT, bool &Replace) {
Replace = false;
DebugLoc dl = Op.getDebugLoc();
if (LoadSDNode *LD = dyn_cast<LoadSDNode>(Op)) {
EVT MemVT = LD->getMemoryVT();
ISD::LoadExtType ExtType = ISD::isNON_EXTLoad(LD)
? (TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT) ? ISD::ZEXTLOAD
: ISD::EXTLOAD)
: LD->getExtensionType();
Replace = true;
return DAG.getExtLoad(ExtType, dl, PVT,
LD->getChain(), LD->getBasePtr(),
LD->getPointerInfo(),
MemVT, LD->isVolatile(),
LD->isNonTemporal(), LD->getAlignment());
}
unsigned Opc = Op.getOpcode();
switch (Opc) {
default: break;
case ISD::AssertSext:
return DAG.getNode(ISD::AssertSext, dl, PVT,
SExtPromoteOperand(Op.getOperand(0), PVT),
Op.getOperand(1));
case ISD::AssertZext:
return DAG.getNode(ISD::AssertZext, dl, PVT,
ZExtPromoteOperand(Op.getOperand(0), PVT),
Op.getOperand(1));
case ISD::Constant: {
unsigned ExtOpc =
Op.getValueType().isByteSized() ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND;
return DAG.getNode(ExtOpc, dl, PVT, Op);
}
}
if (!TLI.isOperationLegal(ISD::ANY_EXTEND, PVT))
return SDValue();
return DAG.getNode(ISD::ANY_EXTEND, dl, PVT, Op);
}
SDValue DAGCombiner::SExtPromoteOperand(SDValue Op, EVT PVT) {
if (!TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, PVT))
return SDValue();
EVT OldVT = Op.getValueType();
DebugLoc dl = Op.getDebugLoc();
bool Replace = false;
SDValue NewOp = PromoteOperand(Op, PVT, Replace);
if (NewOp.getNode() == 0)
return SDValue();
AddToWorkList(NewOp.getNode());
if (Replace)
ReplaceLoadWithPromotedLoad(Op.getNode(), NewOp.getNode());
return DAG.getNode(ISD::SIGN_EXTEND_INREG, dl, NewOp.getValueType(), NewOp,
DAG.getValueType(OldVT));
}
SDValue DAGCombiner::ZExtPromoteOperand(SDValue Op, EVT PVT) {
EVT OldVT = Op.getValueType();
DebugLoc dl = Op.getDebugLoc();
bool Replace = false;
SDValue NewOp = PromoteOperand(Op, PVT, Replace);
if (NewOp.getNode() == 0)
return SDValue();
AddToWorkList(NewOp.getNode());
if (Replace)
ReplaceLoadWithPromotedLoad(Op.getNode(), NewOp.getNode());
return DAG.getZeroExtendInReg(NewOp, dl, OldVT);
}
/// PromoteIntBinOp - Promote the specified integer binary operation if the
/// target indicates it is beneficial. e.g. On x86, it's usually better to
/// promote i16 operations to i32 since i16 instructions are longer.
SDValue DAGCombiner::PromoteIntBinOp(SDValue Op) {
if (!LegalOperations)
return SDValue();
EVT VT = Op.getValueType();
if (VT.isVector() || !VT.isInteger())
return SDValue();
// If operation type is 'undesirable', e.g. i16 on x86, consider
// promoting it.
unsigned Opc = Op.getOpcode();
if (TLI.isTypeDesirableForOp(Opc, VT))
return SDValue();
EVT PVT = VT;
// Consult target whether it is a good idea to promote this operation and
// what's the right type to promote it to.
if (TLI.IsDesirableToPromoteOp(Op, PVT)) {
assert(PVT != VT && "Don't know what type to promote to!");
bool Replace0 = false;
SDValue N0 = Op.getOperand(0);
SDValue NN0 = PromoteOperand(N0, PVT, Replace0);
if (NN0.getNode() == 0)
return SDValue();
bool Replace1 = false;
SDValue N1 = Op.getOperand(1);
SDValue NN1;
if (N0 == N1)
NN1 = NN0;
else {
NN1 = PromoteOperand(N1, PVT, Replace1);
if (NN1.getNode() == 0)
return SDValue();
}
AddToWorkList(NN0.getNode());
if (NN1.getNode())
AddToWorkList(NN1.getNode());
if (Replace0)
ReplaceLoadWithPromotedLoad(N0.getNode(), NN0.getNode());
if (Replace1)
ReplaceLoadWithPromotedLoad(N1.getNode(), NN1.getNode());
DEBUG(dbgs() << "\nPromoting ";
Op.getNode()->dump(&DAG));
DebugLoc dl = Op.getDebugLoc();
return DAG.getNode(ISD::TRUNCATE, dl, VT,
DAG.getNode(Opc, dl, PVT, NN0, NN1));
}
return SDValue();
}
/// PromoteIntShiftOp - Promote the specified integer shift operation if the
/// target indicates it is beneficial. e.g. On x86, it's usually better to
/// promote i16 operations to i32 since i16 instructions are longer.
SDValue DAGCombiner::PromoteIntShiftOp(SDValue Op) {
if (!LegalOperations)
return SDValue();
EVT VT = Op.getValueType();
if (VT.isVector() || !VT.isInteger())
return SDValue();
// If operation type is 'undesirable', e.g. i16 on x86, consider
// promoting it.
unsigned Opc = Op.getOpcode();
if (TLI.isTypeDesirableForOp(Opc, VT))
return SDValue();
EVT PVT = VT;
// Consult target whether it is a good idea to promote this operation and
// what's the right type to promote it to.
if (TLI.IsDesirableToPromoteOp(Op, PVT)) {
assert(PVT != VT && "Don't know what type to promote to!");
bool Replace = false;
SDValue N0 = Op.getOperand(0);
if (Opc == ISD::SRA)
N0 = SExtPromoteOperand(Op.getOperand(0), PVT);
else if (Opc == ISD::SRL)
N0 = ZExtPromoteOperand(Op.getOperand(0), PVT);
else
N0 = PromoteOperand(N0, PVT, Replace);
if (N0.getNode() == 0)
return SDValue();
AddToWorkList(N0.getNode());
if (Replace)
ReplaceLoadWithPromotedLoad(Op.getOperand(0).getNode(), N0.getNode());
DEBUG(dbgs() << "\nPromoting ";
Op.getNode()->dump(&DAG));
DebugLoc dl = Op.getDebugLoc();
return DAG.getNode(ISD::TRUNCATE, dl, VT,
DAG.getNode(Opc, dl, PVT, N0, Op.getOperand(1)));
}
return SDValue();
}
SDValue DAGCombiner::PromoteExtend(SDValue Op) {
if (!LegalOperations)
return SDValue();
EVT VT = Op.getValueType();
if (VT.isVector() || !VT.isInteger())
return SDValue();
// If operation type is 'undesirable', e.g. i16 on x86, consider
// promoting it.
unsigned Opc = Op.getOpcode();
if (TLI.isTypeDesirableForOp(Opc, VT))
return SDValue();
EVT PVT = VT;
// Consult target whether it is a good idea to promote this operation and
// what's the right type to promote it to.
if (TLI.IsDesirableToPromoteOp(Op, PVT)) {
assert(PVT != VT && "Don't know what type to promote to!");
// fold (aext (aext x)) -> (aext x)
// fold (aext (zext x)) -> (zext x)
// fold (aext (sext x)) -> (sext x)
DEBUG(dbgs() << "\nPromoting ";
Op.getNode()->dump(&DAG));
return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), VT, Op.getOperand(0));
}
return SDValue();
}
bool DAGCombiner::PromoteLoad(SDValue Op) {
if (!LegalOperations)
return false;
EVT VT = Op.getValueType();
if (VT.isVector() || !VT.isInteger())
return false;
// If operation type is 'undesirable', e.g. i16 on x86, consider
// promoting it.
unsigned Opc = Op.getOpcode();
if (TLI.isTypeDesirableForOp(Opc, VT))
return false;
EVT PVT = VT;
// Consult target whether it is a good idea to promote this operation and
// what's the right type to promote it to.
if (TLI.IsDesirableToPromoteOp(Op, PVT)) {
assert(PVT != VT && "Don't know what type to promote to!");
DebugLoc dl = Op.getDebugLoc();
SDNode *N = Op.getNode();
LoadSDNode *LD = cast<LoadSDNode>(N);
EVT MemVT = LD->getMemoryVT();
ISD::LoadExtType ExtType = ISD::isNON_EXTLoad(LD)
? (TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT) ? ISD::ZEXTLOAD
: ISD::EXTLOAD)
: LD->getExtensionType();
SDValue NewLD = DAG.getExtLoad(ExtType, dl, PVT,
LD->getChain(), LD->getBasePtr(),
LD->getPointerInfo(),
MemVT, LD->isVolatile(),
LD->isNonTemporal(), LD->getAlignment());
SDValue Result = DAG.getNode(ISD::TRUNCATE, dl, VT, NewLD);
DEBUG(dbgs() << "\nPromoting ";
N->dump(&DAG);
dbgs() << "\nTo: ";
Result.getNode()->dump(&DAG);
dbgs() << '\n');
WorkListRemover DeadNodes(*this);
DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result, &DeadNodes);
DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), NewLD.getValue(1), &DeadNodes);
removeFromWorkList(N);
DAG.DeleteNode(N);
AddToWorkList(Result.getNode());
return true;
}
return false;
}
//===----------------------------------------------------------------------===//
// Main DAG Combiner implementation
//===----------------------------------------------------------------------===//
void DAGCombiner::Run(CombineLevel AtLevel) {
// set the instance variables, so that the various visit routines may use it.
Level = AtLevel;
LegalOperations = Level >= NoIllegalOperations;
LegalTypes = Level >= NoIllegalTypes;
// Add all the dag nodes to the worklist.
WorkList.reserve(DAG.allnodes_size());
for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
E = DAG.allnodes_end(); I != E; ++I)
WorkList.push_back(I);
// Create a dummy node (which is not added to allnodes), that adds a reference
// to the root node, preventing it from being deleted, and tracking any
// changes of the root.
HandleSDNode Dummy(DAG.getRoot());
// The root of the dag may dangle to deleted nodes until the dag combiner is
// done. Set it to null to avoid confusion.
DAG.setRoot(SDValue());
// while the worklist isn't empty, inspect the node on the end of it and
// try and combine it.
while (!WorkList.empty()) {
SDNode *N = WorkList.back();
WorkList.pop_back();
// If N has no uses, it is dead. Make sure to revisit all N's operands once
// N is deleted from the DAG, since they too may now be dead or may have a
// reduced number of uses, allowing other xforms.
if (N->use_empty() && N != &Dummy) {
for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
AddToWorkList(N->getOperand(i).getNode());
DAG.DeleteNode(N);
continue;
}
SDValue RV = combine(N);
if (RV.getNode() == 0)
continue;
++NodesCombined;
// If we get back the same node we passed in, rather than a new node or
// zero, we know that the node must have defined multiple values and
// CombineTo was used. Since CombineTo takes care of the worklist
// mechanics for us, we have no work to do in this case.
if (RV.getNode() == N)
continue;
assert(N->getOpcode() != ISD::DELETED_NODE &&
RV.getNode()->getOpcode() != ISD::DELETED_NODE &&
"Node was deleted but visit returned new node!");
DEBUG(dbgs() << "\nReplacing.3 ";
N->dump(&DAG);
dbgs() << "\nWith: ";
RV.getNode()->dump(&DAG);
dbgs() << '\n');
// Transfer debug value.
DAG.TransferDbgValues(SDValue(N, 0), RV);
WorkListRemover DeadNodes(*this);
if (N->getNumValues() == RV.getNode()->getNumValues())
DAG.ReplaceAllUsesWith(N, RV.getNode(), &DeadNodes);
else {
assert(N->getValueType(0) == RV.getValueType() &&
N->getNumValues() == 1 && "Type mismatch");
SDValue OpV = RV;
DAG.ReplaceAllUsesWith(N, &OpV, &DeadNodes);
}
// Push the new node and any users onto the worklist
AddToWorkList(RV.getNode());
AddUsersToWorkList(RV.getNode());
// Add any uses of the old node to the worklist in case this node is the
// last one that uses them. They may become dead after this node is
// deleted.
for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
AddToWorkList(N->getOperand(i).getNode());
// Finally, if the node is now dead, remove it from the graph. The node
// may not be dead if the replacement process recursively simplified to
// something else needing this node.
if (N->use_empty()) {
// Nodes can be reintroduced into the worklist. Make sure we do not
// process a node that has been replaced.
removeFromWorkList(N);
// Finally, since the node is now dead, remove it from the graph.
DAG.DeleteNode(N);
}
}
// If the root changed (e.g. it was a dead load, update the root).
DAG.setRoot(Dummy.getValue());
}
SDValue DAGCombiner::visit(SDNode *N) {
switch (N->getOpcode()) {
default: break;
case ISD::TokenFactor: return visitTokenFactor(N);
case ISD::MERGE_VALUES: return visitMERGE_VALUES(N);
case ISD::ADD: return visitADD(N);
case ISD::SUB: return visitSUB(N);
case ISD::ADDC: return visitADDC(N);
case ISD::ADDE: return visitADDE(N);
case ISD::MUL: return visitMUL(N);
case ISD::SDIV: return visitSDIV(N);
case ISD::UDIV: return visitUDIV(N);
case ISD::SREM: return visitSREM(N);
case ISD::UREM: return visitUREM(N);
case ISD::MULHU: return visitMULHU(N);
case ISD::MULHS: return visitMULHS(N);
case ISD::SMUL_LOHI: return visitSMUL_LOHI(N);
case ISD::UMUL_LOHI: return visitUMUL_LOHI(N);
case ISD::SMULO: return visitSMULO(N);
case ISD::UMULO: return visitUMULO(N);
case ISD::SDIVREM: return visitSDIVREM(N);
case ISD::UDIVREM: return visitUDIVREM(N);
case ISD::AND: return visitAND(N);
case ISD::OR: return visitOR(N);
case ISD::XOR: return visitXOR(N);
case ISD::SHL: return visitSHL(N);
case ISD::SRA: return visitSRA(N);
case ISD::SRL: return visitSRL(N);
case ISD::CTLZ: return visitCTLZ(N);
case ISD::CTTZ: return visitCTTZ(N);
case ISD::CTPOP: return visitCTPOP(N);
case ISD::SELECT: return visitSELECT(N);
case ISD::SELECT_CC: return visitSELECT_CC(N);
case ISD::SETCC: return visitSETCC(N);
case ISD::SIGN_EXTEND: return visitSIGN_EXTEND(N);
case ISD::ZERO_EXTEND: return visitZERO_EXTEND(N);
case ISD::ANY_EXTEND: return visitANY_EXTEND(N);
case ISD::SIGN_EXTEND_INREG: return visitSIGN_EXTEND_INREG(N);
case ISD::TRUNCATE: return visitTRUNCATE(N);
case ISD::BITCAST: return visitBITCAST(N);
case ISD::BUILD_PAIR: return visitBUILD_PAIR(N);
case ISD::FADD: return visitFADD(N);
case ISD::FSUB: return visitFSUB(N);
case ISD::FMUL: return visitFMUL(N);
case ISD::FDIV: return visitFDIV(N);
case ISD::FREM: return visitFREM(N);
case ISD::FCOPYSIGN: return visitFCOPYSIGN(N);
case ISD::SINT_TO_FP: return visitSINT_TO_FP(N);
case ISD::UINT_TO_FP: return visitUINT_TO_FP(N);
case ISD::FP_TO_SINT: return visitFP_TO_SINT(N);
case ISD::FP_TO_UINT: return visitFP_TO_UINT(N);
case ISD::FP_ROUND: return visitFP_ROUND(N);
case ISD::FP_ROUND_INREG: return visitFP_ROUND_INREG(N);
case ISD::FP_EXTEND: return visitFP_EXTEND(N);
case ISD::FNEG: return visitFNEG(N);
case ISD::FABS: return visitFABS(N);
case ISD::BRCOND: return visitBRCOND(N);
case ISD::BR_CC: return visitBR_CC(N);
case ISD::LOAD: return visitLOAD(N);
case ISD::STORE: return visitSTORE(N);
case ISD::INSERT_VECTOR_ELT: return visitINSERT_VECTOR_ELT(N);
case ISD::EXTRACT_VECTOR_ELT: return visitEXTRACT_VECTOR_ELT(N);
case ISD::BUILD_VECTOR: return visitBUILD_VECTOR(N);
case ISD::CONCAT_VECTORS: return visitCONCAT_VECTORS(N);
case ISD::VECTOR_SHUFFLE: return visitVECTOR_SHUFFLE(N);
case ISD::MEMBARRIER: return visitMEMBARRIER(N);
}
return SDValue();
}
SDValue DAGCombiner::combine(SDNode *N) {
SDValue RV = visit(N);
// If nothing happened, try a target-specific DAG combine.
if (RV.getNode() == 0) {
assert(N->getOpcode() != ISD::DELETED_NODE &&
"Node was deleted but visit returned NULL!");
if (N->getOpcode() >= ISD::BUILTIN_OP_END ||
TLI.hasTargetDAGCombine((ISD::NodeType)N->getOpcode())) {
// Expose the DAG combiner to the target combiner impls.
TargetLowering::DAGCombinerInfo
DagCombineInfo(DAG, !LegalTypes, !LegalOperations, false, this);
RV = TLI.PerformDAGCombine(N, DagCombineInfo);
}
}
// If nothing happened still, try promoting the operation.
if (RV.getNode() == 0) {
switch (N->getOpcode()) {
default: break;
case ISD::ADD:
case ISD::SUB:
case ISD::MUL:
case ISD::AND:
case ISD::OR:
case ISD::XOR:
RV = PromoteIntBinOp(SDValue(N, 0));
break;
case ISD::SHL:
case ISD::SRA:
case ISD::SRL:
RV = PromoteIntShiftOp(SDValue(N, 0));
break;
case ISD::SIGN_EXTEND:
case ISD::ZERO_EXTEND:
case ISD::ANY_EXTEND:
RV = PromoteExtend(SDValue(N, 0));
break;
case ISD::LOAD:
if (PromoteLoad(SDValue(N, 0)))
RV = SDValue(N, 0);
break;
}
}
// If N is a commutative binary node, try commuting it to enable more
// sdisel CSE.
if (RV.getNode() == 0 &&
SelectionDAG::isCommutativeBinOp(N->getOpcode()) &&
N->getNumValues() == 1) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
// Constant operands are canonicalized to RHS.
if (isa<ConstantSDNode>(N0) || !isa<ConstantSDNode>(N1)) {
SDValue Ops[] = { N1, N0 };
SDNode *CSENode = DAG.getNodeIfExists(N->getOpcode(), N->getVTList(),
Ops, 2);
if (CSENode)
return SDValue(CSENode, 0);
}
}
return RV;
}
/// getInputChainForNode - Given a node, return its input chain if it has one,
/// otherwise return a null sd operand.
static SDValue getInputChainForNode(SDNode *N) {
if (unsigned NumOps = N->getNumOperands()) {
if (N->getOperand(0).getValueType() == MVT::Other)
return N->getOperand(0);
else if (N->getOperand(NumOps-1).getValueType() == MVT::Other)
return N->getOperand(NumOps-1);
for (unsigned i = 1; i < NumOps-1; ++i)
if (N->getOperand(i).getValueType() == MVT::Other)
return N->getOperand(i);
}
return SDValue();
}
SDValue DAGCombiner::visitTokenFactor(SDNode *N) {
// If N has two operands, where one has an input chain equal to the other,
// the 'other' chain is redundant.
if (N->getNumOperands() == 2) {
if (getInputChainForNode(N->getOperand(0).getNode()) == N->getOperand(1))
return N->getOperand(0);
if (getInputChainForNode(N->getOperand(1).getNode()) == N->getOperand(0))
return N->getOperand(1);
}
SmallVector<SDNode *, 8> TFs; // List of token factors to visit.
SmallVector<SDValue, 8> Ops; // Ops for replacing token factor.
SmallPtrSet<SDNode*, 16> SeenOps;
bool Changed = false; // If we should replace this token factor.
// Start out with this token factor.
TFs.push_back(N);
// Iterate through token factors. The TFs grows when new token factors are
// encountered.
for (unsigned i = 0; i < TFs.size(); ++i) {
SDNode *TF = TFs[i];
// Check each of the operands.
for (unsigned i = 0, ie = TF->getNumOperands(); i != ie; ++i) {
SDValue Op = TF->getOperand(i);
switch (Op.getOpcode()) {
case ISD::EntryToken:
// Entry tokens don't need to be added to the list. They are
// rededundant.
Changed = true;
break;
case ISD::TokenFactor:
if (Op.hasOneUse() &&
std::find(TFs.begin(), TFs.end(), Op.getNode()) == TFs.end()) {
// Queue up for processing.
TFs.push_back(Op.getNode());
// Clean up in case the token factor is removed.
AddToWorkList(Op.getNode());
Changed = true;
break;
}
// Fall thru
default:
// Only add if it isn't already in the list.
if (SeenOps.insert(Op.getNode()))
Ops.push_back(Op);
else
Changed = true;
break;
}
}
}
SDValue Result;
// If we've change things around then replace token factor.
if (Changed) {
if (Ops.empty()) {
// The entry token is the only possible outcome.
Result = DAG.getEntryNode();
} else {
// New and improved token factor.
Result = DAG.getNode(ISD::TokenFactor, N->getDebugLoc(),
MVT::Other, &Ops[0], Ops.size());
}
// Don't add users to work list.
return CombineTo(N, Result, false);
}
return Result;
}
/// MERGE_VALUES can always be eliminated.
SDValue DAGCombiner::visitMERGE_VALUES(SDNode *N) {
WorkListRemover DeadNodes(*this);
// Replacing results may cause a different MERGE_VALUES to suddenly
// be CSE'd with N, and carry its uses with it. Iterate until no
// uses remain, to ensure that the node can be safely deleted.
do {
for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
DAG.ReplaceAllUsesOfValueWith(SDValue(N, i), N->getOperand(i),
&DeadNodes);
} while (!N->use_empty());
removeFromWorkList(N);
DAG.DeleteNode(N);
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
static
SDValue combineShlAddConstant(DebugLoc DL, SDValue N0, SDValue N1,
SelectionDAG &DAG) {
EVT VT = N0.getValueType();
SDValue N00 = N0.getOperand(0);
SDValue N01 = N0.getOperand(1);
ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N01);
if (N01C && N00.getOpcode() == ISD::ADD && N00.getNode()->hasOneUse() &&
isa<ConstantSDNode>(N00.getOperand(1))) {
// fold (add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<<c2), )
N0 = DAG.getNode(ISD::ADD, N0.getDebugLoc(), VT,
DAG.getNode(ISD::SHL, N00.getDebugLoc(), VT,
N00.getOperand(0), N01),
DAG.getNode(ISD::SHL, N01.getDebugLoc(), VT,
N00.getOperand(1), N01));
return DAG.getNode(ISD::ADD, DL, VT, N0, N1);
}
return SDValue();
}
SDValue DAGCombiner::visitADD(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
EVT VT = N0.getValueType();
// fold vector ops
if (VT.isVector()) {
SDValue FoldedVOp = SimplifyVBinOp(N);
if (FoldedVOp.getNode()) return FoldedVOp;
}
// fold (add x, undef) -> undef
if (N0.getOpcode() == ISD::UNDEF)
return N0;
if (N1.getOpcode() == ISD::UNDEF)
return N1;
// fold (add c1, c2) -> c1+c2
if (N0C && N1C)
return DAG.FoldConstantArithmetic(ISD::ADD, VT, N0C, N1C);
// canonicalize constant to RHS
if (N0C && !N1C)
return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N1, N0);
// fold (add x, 0) -> x
if (N1C && N1C->isNullValue())
return N0;
// fold (add Sym, c) -> Sym+c
if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(N0))
if (!LegalOperations && TLI.isOffsetFoldingLegal(GA) && N1C &&
GA->getOpcode() == ISD::GlobalAddress)
return DAG.getGlobalAddress(GA->getGlobal(), N1C->getDebugLoc(), VT,
GA->getOffset() +
(uint64_t)N1C->getSExtValue());
// fold ((c1-A)+c2) -> (c1+c2)-A
if (N1C && N0.getOpcode() == ISD::SUB)
if (ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getOperand(0)))
return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT,
DAG.getConstant(N1C->getAPIntValue()+
N0C->getAPIntValue(), VT),
N0.getOperand(1));
// reassociate add
SDValue RADD = ReassociateOps(ISD::ADD, N->getDebugLoc(), N0, N1);
if (RADD.getNode() != 0)
return RADD;
// fold ((0-A) + B) -> B-A
if (N0.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N0.getOperand(0)) &&
cast<ConstantSDNode>(N0.getOperand(0))->isNullValue())
return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1, N0.getOperand(1));
// fold (A + (0-B)) -> A-B
if (N1.getOpcode() == ISD::SUB && isa<ConstantSDNode>(N1.getOperand(0)) &&
cast<ConstantSDNode>(N1.getOperand(0))->isNullValue())
return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, N1.getOperand(1));
// fold (A+(B-A)) -> B
if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(1))
return N1.getOperand(0);
// fold ((B-A)+A) -> B
if (N0.getOpcode() == ISD::SUB && N1 == N0.getOperand(1))
return N0.getOperand(0);
// fold (A+(B-(A+C))) to (B-C)
if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD &&
N0 == N1.getOperand(1).getOperand(0))
return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1.getOperand(0),
N1.getOperand(1).getOperand(1));
// fold (A+(B-(C+A))) to (B-C)
if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD &&
N0 == N1.getOperand(1).getOperand(1))
return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1.getOperand(0),
N1.getOperand(1).getOperand(0));
// fold (A+((B-A)+or-C)) to (B+or-C)
if ((N1.getOpcode() == ISD::SUB || N1.getOpcode() == ISD::ADD) &&
N1.getOperand(0).getOpcode() == ISD::SUB &&
N0 == N1.getOperand(0).getOperand(1))
return DAG.getNode(N1.getOpcode(), N->getDebugLoc(), VT,
N1.getOperand(0).getOperand(0), N1.getOperand(1));
// fold (A-B)+(C-D) to (A+C)-(B+D) when A or C is constant
if (N0.getOpcode() == ISD::SUB && N1.getOpcode() == ISD::SUB) {
SDValue N00 = N0.getOperand(0);
SDValue N01 = N0.getOperand(1);
SDValue N10 = N1.getOperand(0);
SDValue N11 = N1.getOperand(1);
if (isa<ConstantSDNode>(N00) || isa<ConstantSDNode>(N10))
return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT,
DAG.getNode(ISD::ADD, N0.getDebugLoc(), VT, N00, N10),
DAG.getNode(ISD::ADD, N1.getDebugLoc(), VT, N01, N11));
}
if (!VT.isVector() && SimplifyDemandedBits(SDValue(N, 0)))
return SDValue(N, 0);
// fold (a+b) -> (a|b) iff a and b share no bits.
if (VT.isInteger() && !VT.isVector()) {
APInt LHSZero, LHSOne;
APInt RHSZero, RHSOne;
APInt Mask = APInt::getAllOnesValue(VT.getScalarType().getSizeInBits());
DAG.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne);
if (LHSZero.getBoolValue()) {
DAG.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne);
// If all possibly-set bits on the LHS are clear on the RHS, return an OR.
// If all possibly-set bits on the RHS are clear on the LHS, return an OR.
if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) ||
(LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask))
return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N1);
}
}
// fold (add (shl (add x, c1), c2), ) -> (add (add (shl x, c2), c1<<c2), )
if (N0.getOpcode() == ISD::SHL && N0.getNode()->hasOneUse()) {
SDValue Result = combineShlAddConstant(N->getDebugLoc(), N0, N1, DAG);
if (Result.getNode()) return Result;
}
if (N1.getOpcode() == ISD::SHL && N1.getNode()->hasOneUse()) {
SDValue Result = combineShlAddConstant(N->getDebugLoc(), N1, N0, DAG);
if (Result.getNode()) return Result;
}
// fold (add x, shl(0 - y, n)) -> sub(x, shl(y, n))
if (N1.getOpcode() == ISD::SHL &&
N1.getOperand(0).getOpcode() == ISD::SUB)
if (ConstantSDNode *C =
dyn_cast<ConstantSDNode>(N1.getOperand(0).getOperand(0)))
if (C->getAPIntValue() == 0)
return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0,
DAG.getNode(ISD::SHL, N->getDebugLoc(), VT,
N1.getOperand(0).getOperand(1),
N1.getOperand(1)));
if (N0.getOpcode() == ISD::SHL &&
N0.getOperand(0).getOpcode() == ISD::SUB)
if (ConstantSDNode *C =
dyn_cast<ConstantSDNode>(N0.getOperand(0).getOperand(0)))
if (C->getAPIntValue() == 0)
return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1,
DAG.getNode(ISD::SHL, N->getDebugLoc(), VT,
N0.getOperand(0).getOperand(1),
N0.getOperand(1)));
if (N1.getOpcode() == ISD::AND) {
SDValue AndOp0 = N1.getOperand(0);
ConstantSDNode *AndOp1 = dyn_cast<ConstantSDNode>(N1->getOperand(1));
unsigned NumSignBits = DAG.ComputeNumSignBits(AndOp0);
unsigned DestBits = VT.getScalarType().getSizeInBits();
// (add z, (and (sbbl x, x), 1)) -> (sub z, (sbbl x, x))
// and similar xforms where the inner op is either ~0 or 0.
if (NumSignBits == DestBits && AndOp1 && AndOp1->isOne()) {
DebugLoc DL = N->getDebugLoc();
return DAG.getNode(ISD::SUB, DL, VT, N->getOperand(0), AndOp0);
}
}
// add (sext i1), X -> sub X, (zext i1)
if (N0.getOpcode() == ISD::SIGN_EXTEND &&
N0.getOperand(0).getValueType() == MVT::i1 &&
!TLI.isOperationLegal(ISD::SIGN_EXTEND, MVT::i1)) {
DebugLoc DL = N->getDebugLoc();
SDValue ZExt = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, N0.getOperand(0));
return DAG.getNode(ISD::SUB, DL, VT, N1, ZExt);
}
return SDValue();
}
SDValue DAGCombiner::visitADDC(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
EVT VT = N0.getValueType();
// If the flag result is dead, turn this into an ADD.
if (N->hasNUsesOfValue(0, 1))
return CombineTo(N, DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N1, N0),
DAG.getNode(ISD::CARRY_FALSE,
N->getDebugLoc(), MVT::Glue));
// canonicalize constant to RHS.
if (N0C && !N1C)
return DAG.getNode(ISD::ADDC, N->getDebugLoc(), N->getVTList(), N1, N0);
// fold (addc x, 0) -> x + no carry out
if (N1C && N1C->isNullValue())
return CombineTo(N, N0, DAG.getNode(ISD::CARRY_FALSE,
N->getDebugLoc(), MVT::Glue));
// fold (addc a, b) -> (or a, b), CARRY_FALSE iff a and b share no bits.
APInt LHSZero, LHSOne;
APInt RHSZero, RHSOne;
APInt Mask = APInt::getAllOnesValue(VT.getScalarType().getSizeInBits());
DAG.ComputeMaskedBits(N0, Mask, LHSZero, LHSOne);
if (LHSZero.getBoolValue()) {
DAG.ComputeMaskedBits(N1, Mask, RHSZero, RHSOne);
// If all possibly-set bits on the LHS are clear on the RHS, return an OR.
// If all possibly-set bits on the RHS are clear on the LHS, return an OR.
if ((RHSZero & (~LHSZero & Mask)) == (~LHSZero & Mask) ||
(LHSZero & (~RHSZero & Mask)) == (~RHSZero & Mask))
return CombineTo(N, DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N1),
DAG.getNode(ISD::CARRY_FALSE,
N->getDebugLoc(), MVT::Glue));
}
return SDValue();
}
SDValue DAGCombiner::visitADDE(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
SDValue CarryIn = N->getOperand(2);
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
// canonicalize constant to RHS
if (N0C && !N1C)
return DAG.getNode(ISD::ADDE, N->getDebugLoc(), N->getVTList(),
N1, N0, CarryIn);
// fold (adde x, y, false) -> (addc x, y)
if (CarryIn.getOpcode() == ISD::CARRY_FALSE)
return DAG.getNode(ISD::ADDC, N->getDebugLoc(), N->getVTList(), N1, N0);
return SDValue();
}
// Since it may not be valid to emit a fold to zero for vector initializers
// check if we can before folding.
static SDValue tryFoldToZero(DebugLoc DL, const TargetLowering &TLI, EVT VT,
SelectionDAG &DAG, bool LegalOperations) {
if (!VT.isVector()) {
return DAG.getConstant(0, VT);
}
if (!LegalOperations || TLI.isOperationLegal(ISD::BUILD_VECTOR, VT)) {
// Produce a vector of zeros.
SDValue El = DAG.getConstant(0, VT.getVectorElementType());
std::vector<SDValue> Ops(VT.getVectorNumElements(), El);
return DAG.getNode(ISD::BUILD_VECTOR, DL, VT,
&Ops[0], Ops.size());
}
return SDValue();
}
SDValue DAGCombiner::visitSUB(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode());
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode());
ConstantSDNode *N1C1 = N1.getOpcode() != ISD::ADD ? 0 :
dyn_cast<ConstantSDNode>(N1.getOperand(1).getNode());
EVT VT = N0.getValueType();
// fold vector ops
if (VT.isVector()) {
SDValue FoldedVOp = SimplifyVBinOp(N);
if (FoldedVOp.getNode()) return FoldedVOp;
}
// fold (sub x, x) -> 0
// FIXME: Refactor this and xor and other similar operations together.
if (N0 == N1)
return tryFoldToZero(N->getDebugLoc(), TLI, VT, DAG, LegalOperations);
// fold (sub c1, c2) -> c1-c2
if (N0C && N1C)
return DAG.FoldConstantArithmetic(ISD::SUB, VT, N0C, N1C);
// fold (sub x, c) -> (add x, -c)
if (N1C)
return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N0,
DAG.getConstant(-N1C->getAPIntValue(), VT));
// Canonicalize (sub -1, x) -> ~x, i.e. (xor x, -1)
if (N0C && N0C->isAllOnesValue())
return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N1, N0);
// fold A-(A-B) -> B
if (N1.getOpcode() == ISD::SUB && N0 == N1.getOperand(0))
return N1.getOperand(1);
// fold (A+B)-A -> B
if (N0.getOpcode() == ISD::ADD && N0.getOperand(0) == N1)
return N0.getOperand(1);
// fold (A+B)-B -> A
if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1)
return N0.getOperand(0);
// fold C2-(A+C1) -> (C2-C1)-A
if (N1.getOpcode() == ISD::ADD && N0C && N1C1) {
SDValue NewC = DAG.getConstant((N0C->getAPIntValue() - N1C1->getAPIntValue()), VT);
return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, NewC,
N1.getOperand(0));
}
// fold ((A+(B+or-C))-B) -> A+or-C
if (N0.getOpcode() == ISD::ADD &&
(N0.getOperand(1).getOpcode() == ISD::SUB ||
N0.getOperand(1).getOpcode() == ISD::ADD) &&
N0.getOperand(1).getOperand(0) == N1)
return DAG.getNode(N0.getOperand(1).getOpcode(), N->getDebugLoc(), VT,
N0.getOperand(0), N0.getOperand(1).getOperand(1));
// fold ((A+(C+B))-B) -> A+C
if (N0.getOpcode() == ISD::ADD &&
N0.getOperand(1).getOpcode() == ISD::ADD &&
N0.getOperand(1).getOperand(1) == N1)
return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT,
N0.getOperand(0), N0.getOperand(1).getOperand(0));
// fold ((A-(B-C))-C) -> A-B
if (N0.getOpcode() == ISD::SUB &&
N0.getOperand(1).getOpcode() == ISD::SUB &&
N0.getOperand(1).getOperand(1) == N1)
return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT,
N0.getOperand(0), N0.getOperand(1).getOperand(0));
// If either operand of a sub is undef, the result is undef
if (N0.getOpcode() == ISD::UNDEF)
return N0;
if (N1.getOpcode() == ISD::UNDEF)
return N1;
// If the relocation model supports it, consider symbol offsets.
if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(N0))
if (!LegalOperations && TLI.isOffsetFoldingLegal(GA)) {
// fold (sub Sym, c) -> Sym-c
if (N1C && GA->getOpcode() == ISD::GlobalAddress)
return DAG.getGlobalAddress(GA->getGlobal(), N1C->getDebugLoc(), VT,
GA->getOffset() -
(uint64_t)N1C->getSExtValue());
// fold (sub Sym+c1, Sym+c2) -> c1-c2
if (GlobalAddressSDNode *GB = dyn_cast<GlobalAddressSDNode>(N1))
if (GA->getGlobal() == GB->getGlobal())
return DAG.getConstant((uint64_t)GA->getOffset() - GB->getOffset(),
VT);
}
return SDValue();
}
SDValue DAGCombiner::visitMUL(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
EVT VT = N0.getValueType();
// fold vector ops
if (VT.isVector()) {
SDValue FoldedVOp = SimplifyVBinOp(N);
if (FoldedVOp.getNode()) return FoldedVOp;
}
// fold (mul x, undef) -> 0
if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)
return DAG.getConstant(0, VT);
// fold (mul c1, c2) -> c1*c2
if (N0C && N1C)
return DAG.FoldConstantArithmetic(ISD::MUL, VT, N0C, N1C);
// canonicalize constant to RHS
if (N0C && !N1C)
return DAG.getNode(ISD::MUL, N->getDebugLoc(), VT, N1, N0);
// fold (mul x, 0) -> 0
if (N1C && N1C->isNullValue())
return N1;
// fold (mul x, -1) -> 0-x
if (N1C && N1C->isAllOnesValue())
return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT,
DAG.getConstant(0, VT), N0);
// fold (mul x, (1 << c)) -> x << c
if (N1C && N1C->getAPIntValue().isPowerOf2())
return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0,
DAG.getConstant(N1C->getAPIntValue().logBase2(),
getShiftAmountTy(N0.getValueType())));
// fold (mul x, -(1 << c)) -> -(x << c) or (-x) << c
if (N1C && (-N1C->getAPIntValue()).isPowerOf2()) {
unsigned Log2Val = (-N1C->getAPIntValue()).logBase2();
// FIXME: If the input is something that is easily negated (e.g. a
// single-use add), we should put the negate there.
return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT,
DAG.getConstant(0, VT),
DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0,
DAG.getConstant(Log2Val,
getShiftAmountTy(N0.getValueType()))));
}
// (mul (shl X, c1), c2) -> (mul X, c2 << c1)
if (N1C && N0.getOpcode() == ISD::SHL &&
isa<ConstantSDNode>(N0.getOperand(1))) {
SDValue C3 = DAG.getNode(ISD::SHL, N->getDebugLoc(), VT,
N1, N0.getOperand(1));
AddToWorkList(C3.getNode());
return DAG.getNode(ISD::MUL, N->getDebugLoc(), VT,
N0.getOperand(0), C3);
}
// Change (mul (shl X, C), Y) -> (shl (mul X, Y), C) when the shift has one
// use.
{
SDValue Sh(0,0), Y(0,0);
// Check for both (mul (shl X, C), Y) and (mul Y, (shl X, C)).
if (N0.getOpcode() == ISD::SHL && isa<ConstantSDNode>(N0.getOperand(1)) &&
N0.getNode()->hasOneUse()) {
Sh = N0; Y = N1;
} else if (N1.getOpcode() == ISD::SHL &&
isa<ConstantSDNode>(N1.getOperand(1)) &&
N1.getNode()->hasOneUse()) {
Sh = N1; Y = N0;
}
if (Sh.getNode()) {
SDValue Mul = DAG.getNode(ISD::MUL, N->getDebugLoc(), VT,
Sh.getOperand(0), Y);
return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT,
Mul, Sh.getOperand(1));
}
}
// fold (mul (add x, c1), c2) -> (add (mul x, c2), c1*c2)
if (N1C && N0.getOpcode() == ISD::ADD && N0.getNode()->hasOneUse() &&
isa<ConstantSDNode>(N0.getOperand(1)))
return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT,
DAG.getNode(ISD::MUL, N0.getDebugLoc(), VT,
N0.getOperand(0), N1),
DAG.getNode(ISD::MUL, N1.getDebugLoc(), VT,
N0.getOperand(1), N1));
// reassociate mul
SDValue RMUL = ReassociateOps(ISD::MUL, N->getDebugLoc(), N0, N1);
if (RMUL.getNode() != 0)
return RMUL;
return SDValue();
}
SDValue DAGCombiner::visitSDIV(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode());
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode());
EVT VT = N->getValueType(0);
// fold vector ops
if (VT.isVector()) {
SDValue FoldedVOp = SimplifyVBinOp(N);
if (FoldedVOp.getNode()) return FoldedVOp;
}
// fold (sdiv c1, c2) -> c1/c2
if (N0C && N1C && !N1C->isNullValue())
return DAG.FoldConstantArithmetic(ISD::SDIV, VT, N0C, N1C);
// fold (sdiv X, 1) -> X
if (N1C && N1C->getSExtValue() == 1LL)
return N0;
// fold (sdiv X, -1) -> 0-X
if (N1C && N1C->isAllOnesValue())
return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT,
DAG.getConstant(0, VT), N0);
// If we know the sign bits of both operands are zero, strength reduce to a
// udiv instead. Handles (X&15) /s 4 -> X&15 >> 2
if (!VT.isVector()) {
if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0))
return DAG.getNode(ISD::UDIV, N->getDebugLoc(), N1.getValueType(),
N0, N1);
}
// fold (sdiv X, pow2) -> simple ops after legalize
if (N1C && !N1C->isNullValue() && !TLI.isIntDivCheap() &&
(isPowerOf2_64(N1C->getSExtValue()) ||
isPowerOf2_64(-N1C->getSExtValue()))) {
// If dividing by powers of two is cheap, then don't perform the following
// fold.
if (TLI.isPow2DivCheap())
return SDValue();
int64_t pow2 = N1C->getSExtValue();
int64_t abs2 = pow2 > 0 ? pow2 : -pow2;
unsigned lg2 = Log2_64(abs2);
// Splat the sign bit into the register
SDValue SGN = DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, N0,
DAG.getConstant(VT.getSizeInBits()-1,
getShiftAmountTy(N0.getValueType())));
AddToWorkList(SGN.getNode());
// Add (N0 < 0) ? abs2 - 1 : 0;
SDValue SRL = DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, SGN,
DAG.getConstant(VT.getSizeInBits() - lg2,
getShiftAmountTy(SGN.getValueType())));
SDValue ADD = DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N0, SRL);
AddToWorkList(SRL.getNode());
AddToWorkList(ADD.getNode()); // Divide by pow2
SDValue SRA = DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, ADD,
DAG.getConstant(lg2, getShiftAmountTy(ADD.getValueType())));
// If we're dividing by a positive value, we're done. Otherwise, we must
// negate the result.
if (pow2 > 0)
return SRA;
AddToWorkList(SRA.getNode());
return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT,
DAG.getConstant(0, VT), SRA);
}
// if integer divide is expensive and we satisfy the requirements, emit an
// alternate sequence.
if (N1C && (N1C->getSExtValue() < -1 || N1C->getSExtValue() > 1) &&
!TLI.isIntDivCheap()) {
SDValue Op = BuildSDIV(N);
if (Op.getNode()) return Op;
}
// undef / X -> 0
if (N0.getOpcode() == ISD::UNDEF)
return DAG.getConstant(0, VT);
// X / undef -> undef
if (N1.getOpcode() == ISD::UNDEF)
return N1;
return SDValue();
}
SDValue DAGCombiner::visitUDIV(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode());
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode());
EVT VT = N->getValueType(0);
// fold vector ops
if (VT.isVector()) {
SDValue FoldedVOp = SimplifyVBinOp(N);
if (FoldedVOp.getNode()) return FoldedVOp;
}
// fold (udiv c1, c2) -> c1/c2
if (N0C && N1C && !N1C->isNullValue())
return DAG.FoldConstantArithmetic(ISD::UDIV, VT, N0C, N1C);
// fold (udiv x, (1 << c)) -> x >>u c
if (N1C && N1C->getAPIntValue().isPowerOf2())
return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0,
DAG.getConstant(N1C->getAPIntValue().logBase2(),
getShiftAmountTy(N0.getValueType())));
// fold (udiv x, (shl c, y)) -> x >>u (log2(c)+y) iff c is power of 2
if (N1.getOpcode() == ISD::SHL) {
if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) {
if (SHC->getAPIntValue().isPowerOf2()) {
EVT ADDVT = N1.getOperand(1).getValueType();
SDValue Add = DAG.getNode(ISD::ADD, N->getDebugLoc(), ADDVT,
N1.getOperand(1),
DAG.getConstant(SHC->getAPIntValue()
.logBase2(),
ADDVT));
AddToWorkList(Add.getNode());
return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0, Add);
}
}
}
// fold (udiv x, c) -> alternate
if (N1C && !N1C->isNullValue() && !TLI.isIntDivCheap()) {
SDValue Op = BuildUDIV(N);
if (Op.getNode()) return Op;
}
// undef / X -> 0
if (N0.getOpcode() == ISD::UNDEF)
return DAG.getConstant(0, VT);
// X / undef -> undef
if (N1.getOpcode() == ISD::UNDEF)
return N1;
return SDValue();
}
SDValue DAGCombiner::visitSREM(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
EVT VT = N->getValueType(0);
// fold (srem c1, c2) -> c1%c2
if (N0C && N1C && !N1C->isNullValue())
return DAG.FoldConstantArithmetic(ISD::SREM, VT, N0C, N1C);
// If we know the sign bits of both operands are zero, strength reduce to a
// urem instead. Handles (X & 0x0FFFFFFF) %s 16 -> X&15
if (!VT.isVector()) {
if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0))
return DAG.getNode(ISD::UREM, N->getDebugLoc(), VT, N0, N1);
}
// If X/C can be simplified by the division-by-constant logic, lower
// X%C to the equivalent of X-X/C*C.
if (N1C && !N1C->isNullValue()) {
SDValue Div = DAG.getNode(ISD::SDIV, N->getDebugLoc(), VT, N0, N1);
AddToWorkList(Div.getNode());
SDValue OptimizedDiv = combine(Div.getNode());
if (OptimizedDiv.getNode() && OptimizedDiv.getNode() != Div.getNode()) {
SDValue Mul = DAG.getNode(ISD::MUL, N->getDebugLoc(), VT,
OptimizedDiv, N1);
SDValue Sub = DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, Mul);
AddToWorkList(Mul.getNode());
return Sub;
}
}
// undef % X -> 0
if (N0.getOpcode() == ISD::UNDEF)
return DAG.getConstant(0, VT);
// X % undef -> undef
if (N1.getOpcode() == ISD::UNDEF)
return N1;
return SDValue();
}
SDValue DAGCombiner::visitUREM(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
EVT VT = N->getValueType(0);
// fold (urem c1, c2) -> c1%c2
if (N0C && N1C && !N1C->isNullValue())
return DAG.FoldConstantArithmetic(ISD::UREM, VT, N0C, N1C);
// fold (urem x, pow2) -> (and x, pow2-1)
if (N1C && !N1C->isNullValue() && N1C->getAPIntValue().isPowerOf2())
return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0,
DAG.getConstant(N1C->getAPIntValue()-1,VT));
// fold (urem x, (shl pow2, y)) -> (and x, (add (shl pow2, y), -1))
if (N1.getOpcode() == ISD::SHL) {
if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) {
if (SHC->getAPIntValue().isPowerOf2()) {
SDValue Add =
DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N1,
DAG.getConstant(APInt::getAllOnesValue(VT.getSizeInBits()),
VT));
AddToWorkList(Add.getNode());
return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, Add);
}
}
}
// If X/C can be simplified by the division-by-constant logic, lower
// X%C to the equivalent of X-X/C*C.
if (N1C && !N1C->isNullValue()) {
SDValue Div = DAG.getNode(ISD::UDIV, N->getDebugLoc(), VT, N0, N1);
AddToWorkList(Div.getNode());
SDValue OptimizedDiv = combine(Div.getNode());
if (OptimizedDiv.getNode() && OptimizedDiv.getNode() != Div.getNode()) {
SDValue Mul = DAG.getNode(ISD::MUL, N->getDebugLoc(), VT,
OptimizedDiv, N1);
SDValue Sub = DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0, Mul);
AddToWorkList(Mul.getNode());
return Sub;
}
}
// undef % X -> 0
if (N0.getOpcode() == ISD::UNDEF)
return DAG.getConstant(0, VT);
// X % undef -> undef
if (N1.getOpcode() == ISD::UNDEF)
return N1;
return SDValue();
}
SDValue DAGCombiner::visitMULHS(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
EVT VT = N->getValueType(0);
DebugLoc DL = N->getDebugLoc();
// fold (mulhs x, 0) -> 0
if (N1C && N1C->isNullValue())
return N1;
// fold (mulhs x, 1) -> (sra x, size(x)-1)
if (N1C && N1C->getAPIntValue() == 1)
return DAG.getNode(ISD::SRA, N->getDebugLoc(), N0.getValueType(), N0,
DAG.getConstant(N0.getValueType().getSizeInBits() - 1,
getShiftAmountTy(N0.getValueType())));
// fold (mulhs x, undef) -> 0
if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)
return DAG.getConstant(0, VT);
// If the type twice as wide is legal, transform the mulhs to a wider multiply
// plus a shift.
if (VT.isSimple() && !VT.isVector()) {
MVT Simple = VT.getSimpleVT();
unsigned SimpleSize = Simple.getSizeInBits();
EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2);
if (TLI.isOperationLegal(ISD::MUL, NewVT)) {
N0 = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N0);
N1 = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N1);
N1 = DAG.getNode(ISD::MUL, DL, NewVT, N0, N1);
N1 = DAG.getNode(ISD::SRL, DL, NewVT, N1,
DAG.getConstant(SimpleSize, getShiftAmountTy(N1.getValueType())));
return DAG.getNode(ISD::TRUNCATE, DL, VT, N1);
}
}
return SDValue();
}
SDValue DAGCombiner::visitMULHU(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
EVT VT = N->getValueType(0);
DebugLoc DL = N->getDebugLoc();
// fold (mulhu x, 0) -> 0
if (N1C && N1C->isNullValue())
return N1;
// fold (mulhu x, 1) -> 0
if (N1C && N1C->getAPIntValue() == 1)
return DAG.getConstant(0, N0.getValueType());
// fold (mulhu x, undef) -> 0
if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)
return DAG.getConstant(0, VT);
// If the type twice as wide is legal, transform the mulhu to a wider multiply
// plus a shift.
if (VT.isSimple() && !VT.isVector()) {
MVT Simple = VT.getSimpleVT();
unsigned SimpleSize = Simple.getSizeInBits();
EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2);
if (TLI.isOperationLegal(ISD::MUL, NewVT)) {
N0 = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N0);
N1 = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N1);
N1 = DAG.getNode(ISD::MUL, DL, NewVT, N0, N1);
N1 = DAG.getNode(ISD::SRL, DL, NewVT, N1,
DAG.getConstant(SimpleSize, getShiftAmountTy(N1.getValueType())));
return DAG.getNode(ISD::TRUNCATE, DL, VT, N1);
}
}
return SDValue();
}
/// SimplifyNodeWithTwoResults - Perform optimizations common to nodes that
/// compute two values. LoOp and HiOp give the opcodes for the two computations
/// that are being performed. Return true if a simplification was made.
///
SDValue DAGCombiner::SimplifyNodeWithTwoResults(SDNode *N, unsigned LoOp,
unsigned HiOp) {
// If the high half is not needed, just compute the low half.
bool HiExists = N->hasAnyUseOfValue(1);
if (!HiExists &&
(!LegalOperations ||
TLI.isOperationLegal(LoOp, N->getValueType(0)))) {
SDValue Res = DAG.getNode(LoOp, N->getDebugLoc(), N->getValueType(0),
N->op_begin(), N->getNumOperands());
return CombineTo(N, Res, Res);
}
// If the low half is not needed, just compute the high half.
bool LoExists = N->hasAnyUseOfValue(0);
if (!LoExists &&
(!LegalOperations ||
TLI.isOperationLegal(HiOp, N->getValueType(1)))) {
SDValue Res = DAG.getNode(HiOp, N->getDebugLoc(), N->getValueType(1),
N->op_begin(), N->getNumOperands());
return CombineTo(N, Res, Res);
}
// If both halves are used, return as it is.
if (LoExists && HiExists)
return SDValue();
// If the two computed results can be simplified separately, separate them.
if (LoExists) {
SDValue Lo = DAG.getNode(LoOp, N->getDebugLoc(), N->getValueType(0),
N->op_begin(), N->getNumOperands());
AddToWorkList(Lo.getNode());
SDValue LoOpt = combine(Lo.getNode());
if (LoOpt.getNode() && LoOpt.getNode() != Lo.getNode() &&
(!LegalOperations ||
TLI.isOperationLegal(LoOpt.getOpcode(), LoOpt.getValueType())))
return CombineTo(N, LoOpt, LoOpt);
}
if (HiExists) {
SDValue Hi = DAG.getNode(HiOp, N->getDebugLoc(), N->getValueType(1),
N->op_begin(), N->getNumOperands());
AddToWorkList(Hi.getNode());
SDValue HiOpt = combine(Hi.getNode());
if (HiOpt.getNode() && HiOpt != Hi &&
(!LegalOperations ||
TLI.isOperationLegal(HiOpt.getOpcode(), HiOpt.getValueType())))
return CombineTo(N, HiOpt, HiOpt);
}
return SDValue();
}
SDValue DAGCombiner::visitSMUL_LOHI(SDNode *N) {
SDValue Res = SimplifyNodeWithTwoResults(N, ISD::MUL, ISD::MULHS);
if (Res.getNode()) return Res;
EVT VT = N->getValueType(0);
DebugLoc DL = N->getDebugLoc();
// If the type twice as wide is legal, transform the mulhu to a wider multiply
// plus a shift.
if (VT.isSimple() && !VT.isVector()) {
MVT Simple = VT.getSimpleVT();
unsigned SimpleSize = Simple.getSizeInBits();
EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2);
if (TLI.isOperationLegal(ISD::MUL, NewVT)) {
SDValue Lo = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N->getOperand(0));
SDValue Hi = DAG.getNode(ISD::SIGN_EXTEND, DL, NewVT, N->getOperand(1));
Lo = DAG.getNode(ISD::MUL, DL, NewVT, Lo, Hi);
// Compute the high part as N1.
Hi = DAG.getNode(ISD::SRL, DL, NewVT, Lo,
DAG.getConstant(SimpleSize, getShiftAmountTy(Lo.getValueType())));
Hi = DAG.getNode(ISD::TRUNCATE, DL, VT, Hi);
// Compute the low part as N0.
Lo = DAG.getNode(ISD::TRUNCATE, DL, VT, Lo);
return CombineTo(N, Lo, Hi);
}
}
return SDValue();
}
SDValue DAGCombiner::visitUMUL_LOHI(SDNode *N) {
SDValue Res = SimplifyNodeWithTwoResults(N, ISD::MUL, ISD::MULHU);
if (Res.getNode()) return Res;
EVT VT = N->getValueType(0);
DebugLoc DL = N->getDebugLoc();
// If the type twice as wide is legal, transform the mulhu to a wider multiply
// plus a shift.
if (VT.isSimple() && !VT.isVector()) {
MVT Simple = VT.getSimpleVT();
unsigned SimpleSize = Simple.getSizeInBits();
EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), SimpleSize*2);
if (TLI.isOperationLegal(ISD::MUL, NewVT)) {
SDValue Lo = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N->getOperand(0));
SDValue Hi = DAG.getNode(ISD::ZERO_EXTEND, DL, NewVT, N->getOperand(1));
Lo = DAG.getNode(ISD::MUL, DL, NewVT, Lo, Hi);
// Compute the high part as N1.
Hi = DAG.getNode(ISD::SRL, DL, NewVT, Lo,
DAG.getConstant(SimpleSize, getShiftAmountTy(Lo.getValueType())));
Hi = DAG.getNode(ISD::TRUNCATE, DL, VT, Hi);
// Compute the low part as N0.
Lo = DAG.getNode(ISD::TRUNCATE, DL, VT, Lo);
return CombineTo(N, Lo, Hi);
}
}
return SDValue();
}
SDValue DAGCombiner::visitSMULO(SDNode *N) {
// (smulo x, 2) -> (saddo x, x)
if (ConstantSDNode *C2 = dyn_cast<ConstantSDNode>(N->getOperand(1)))
if (C2->getAPIntValue() == 2)
return DAG.getNode(ISD::SADDO, N->getDebugLoc(), N->getVTList(),
N->getOperand(0), N->getOperand(0));
return SDValue();
}
SDValue DAGCombiner::visitUMULO(SDNode *N) {
// (umulo x, 2) -> (uaddo x, x)
if (ConstantSDNode *C2 = dyn_cast<ConstantSDNode>(N->getOperand(1)))
if (C2->getAPIntValue() == 2)
return DAG.getNode(ISD::UADDO, N->getDebugLoc(), N->getVTList(),
N->getOperand(0), N->getOperand(0));
return SDValue();
}
SDValue DAGCombiner::visitSDIVREM(SDNode *N) {
SDValue Res = SimplifyNodeWithTwoResults(N, ISD::SDIV, ISD::SREM);
if (Res.getNode()) return Res;
return SDValue();
}
SDValue DAGCombiner::visitUDIVREM(SDNode *N) {
SDValue Res = SimplifyNodeWithTwoResults(N, ISD::UDIV, ISD::UREM);
if (Res.getNode()) return Res;
return SDValue();
}
/// SimplifyBinOpWithSameOpcodeHands - If this is a binary operator with
/// two operands of the same opcode, try to simplify it.
SDValue DAGCombiner::SimplifyBinOpWithSameOpcodeHands(SDNode *N) {
SDValue N0 = N->getOperand(0), N1 = N->getOperand(1);
EVT VT = N0.getValueType();
assert(N0.getOpcode() == N1.getOpcode() && "Bad input!");
// Bail early if none of these transforms apply.
if (N0.getNode()->getNumOperands() == 0) return SDValue();
// For each of OP in AND/OR/XOR:
// fold (OP (zext x), (zext y)) -> (zext (OP x, y))
// fold (OP (sext x), (sext y)) -> (sext (OP x, y))
// fold (OP (aext x), (aext y)) -> (aext (OP x, y))
// fold (OP (trunc x), (trunc y)) -> (trunc (OP x, y)) (if trunc isn't free)
//
// do not sink logical op inside of a vector extend, since it may combine
// into a vsetcc.
EVT Op0VT = N0.getOperand(0).getValueType();
if ((N0.getOpcode() == ISD::ZERO_EXTEND ||
N0.getOpcode() == ISD::SIGN_EXTEND ||
// Avoid infinite looping with PromoteIntBinOp.
(N0.getOpcode() == ISD::ANY_EXTEND &&
(!LegalTypes || TLI.isTypeDesirableForOp(N->getOpcode(), Op0VT))) ||
(N0.getOpcode() == ISD::TRUNCATE &&
(!TLI.isZExtFree(VT, Op0VT) ||
!TLI.isTruncateFree(Op0VT, VT)) &&
TLI.isTypeLegal(Op0VT))) &&
!VT.isVector() &&
Op0VT == N1.getOperand(0).getValueType() &&
(!LegalOperations || TLI.isOperationLegal(N->getOpcode(), Op0VT))) {
SDValue ORNode = DAG.getNode(N->getOpcode(), N0.getDebugLoc(),
N0.getOperand(0).getValueType(),
N0.getOperand(0), N1.getOperand(0));
AddToWorkList(ORNode.getNode());
return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, ORNode);
}
// For each of OP in SHL/SRL/SRA/AND...
// fold (and (OP x, z), (OP y, z)) -> (OP (and x, y), z)
// fold (or (OP x, z), (OP y, z)) -> (OP (or x, y), z)
// fold (xor (OP x, z), (OP y, z)) -> (OP (xor x, y), z)
if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL ||
N0.getOpcode() == ISD::SRA || N0.getOpcode() == ISD::AND) &&
N0.getOperand(1) == N1.getOperand(1)) {
SDValue ORNode = DAG.getNode(N->getOpcode(), N0.getDebugLoc(),
N0.getOperand(0).getValueType(),
N0.getOperand(0), N1.getOperand(0));
AddToWorkList(ORNode.getNode());
return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT,
ORNode, N0.getOperand(1));
}
return SDValue();
}
SDValue DAGCombiner::visitAND(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
SDValue LL, LR, RL, RR, CC0, CC1;
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
EVT VT = N1.getValueType();
unsigned BitWidth = VT.getScalarType().getSizeInBits();
// fold vector ops
if (VT.isVector()) {
SDValue FoldedVOp = SimplifyVBinOp(N);
if (FoldedVOp.getNode()) return FoldedVOp;
}
// fold (and x, undef) -> 0
if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)
return DAG.getConstant(0, VT);
// fold (and c1, c2) -> c1&c2
if (N0C && N1C)
return DAG.FoldConstantArithmetic(ISD::AND, VT, N0C, N1C);
// canonicalize constant to RHS
if (N0C && !N1C)
return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N1, N0);
// fold (and x, -1) -> x
if (N1C && N1C->isAllOnesValue())
return N0;
// if (and x, c) is known to be zero, return 0
if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0),
APInt::getAllOnesValue(BitWidth)))
return DAG.getConstant(0, VT);
// reassociate and
SDValue RAND = ReassociateOps(ISD::AND, N->getDebugLoc(), N0, N1);
if (RAND.getNode() != 0)
return RAND;
// fold (and (or x, C), D) -> D if (C & D) == D
if (N1C && N0.getOpcode() == ISD::OR)
if (ConstantSDNode *ORI = dyn_cast<ConstantSDNode>(N0.getOperand(1)))
if ((ORI->getAPIntValue() & N1C->getAPIntValue()) == N1C->getAPIntValue())
return N1;
// fold (and (any_ext V), c) -> (zero_ext V) if 'and' only clears top bits.
if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) {
SDValue N0Op0 = N0.getOperand(0);
APInt Mask = ~N1C->getAPIntValue();
Mask = Mask.trunc(N0Op0.getValueSizeInBits());
if (DAG.MaskedValueIsZero(N0Op0, Mask)) {
SDValue Zext = DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(),
N0.getValueType(), N0Op0);
// Replace uses of the AND with uses of the Zero extend node.
CombineTo(N, Zext);
// We actually want to replace all uses of the any_extend with the
// zero_extend, to avoid duplicating things. This will later cause this
// AND to be folded.
CombineTo(N0.getNode(), Zext);
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
}
// fold (and (setcc x), (setcc y)) -> (setcc (and x, y))
if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){
ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get();
ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get();
if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 &&
LL.getValueType().isInteger()) {
// fold (and (seteq X, 0), (seteq Y, 0)) -> (seteq (or X, Y), 0)
if (cast<ConstantSDNode>(LR)->isNullValue() && Op1 == ISD::SETEQ) {
SDValue ORNode = DAG.getNode(ISD::OR, N0.getDebugLoc(),
LR.getValueType(), LL, RL);
AddToWorkList(ORNode.getNode());
return DAG.getSetCC(N->getDebugLoc(), VT, ORNode, LR, Op1);
}
// fold (and (seteq X, -1), (seteq Y, -1)) -> (seteq (and X, Y), -1)
if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETEQ) {
SDValue ANDNode = DAG.getNode(ISD::AND, N0.getDebugLoc(),
LR.getValueType(), LL, RL);
AddToWorkList(ANDNode.getNode());
return DAG.getSetCC(N->getDebugLoc(), VT, ANDNode, LR, Op1);
}
// fold (and (setgt X, -1), (setgt Y, -1)) -> (setgt (or X, Y), -1)
if (cast<ConstantSDNode>(LR)->isAllOnesValue() && Op1 == ISD::SETGT) {
SDValue ORNode = DAG.getNode(ISD::OR, N0.getDebugLoc(),
LR.getValueType(), LL, RL);
AddToWorkList(ORNode.getNode());
return DAG.getSetCC(N->getDebugLoc(), VT, ORNode, LR, Op1);
}
}
// canonicalize equivalent to ll == rl
if (LL == RR && LR == RL) {
Op1 = ISD::getSetCCSwappedOperands(Op1);
std::swap(RL, RR);
}
if (LL == RL && LR == RR) {
bool isInteger = LL.getValueType().isInteger();
ISD::CondCode Result = ISD::getSetCCAndOperation(Op0, Op1, isInteger);
if (Result != ISD::SETCC_INVALID &&
(!LegalOperations || TLI.isCondCodeLegal(Result, LL.getValueType())))
return DAG.getSetCC(N->getDebugLoc(), N0.getValueType(),
LL, LR, Result);
}
}
// Simplify: (and (op x...), (op y...)) -> (op (and x, y))
if (N0.getOpcode() == N1.getOpcode()) {
SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N);
if (Tmp.getNode()) return Tmp;
}
// fold (and (sign_extend_inreg x, i16 to i32), 1) -> (and x, 1)
// fold (and (sra)) -> (and (srl)) when possible.
if (!VT.isVector() &&
SimplifyDemandedBits(SDValue(N, 0)))
return SDValue(N, 0);
// fold (zext_inreg (extload x)) -> (zextload x)
if (ISD::isEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode())) {
LoadSDNode *LN0 = cast<LoadSDNode>(N0);
EVT MemVT = LN0->getMemoryVT();
// If we zero all the possible extended bits, then we can turn this into
// a zextload if we are running before legalize or the operation is legal.
unsigned BitWidth = N1.getValueType().getScalarType().getSizeInBits();
if (DAG.MaskedValueIsZero(N1, APInt::getHighBitsSet(BitWidth,
BitWidth - MemVT.getScalarType().getSizeInBits())) &&
((!LegalOperations && !LN0->isVolatile()) ||
TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT))) {
SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, N0.getDebugLoc(), VT,
LN0->getChain(), LN0->getBasePtr(),
LN0->getPointerInfo(), MemVT,
LN0->isVolatile(), LN0->isNonTemporal(),
LN0->getAlignment());
AddToWorkList(N);
CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1));
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
}
// fold (zext_inreg (sextload x)) -> (zextload x) iff load has one use
if (ISD::isSEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) &&
N0.hasOneUse()) {
LoadSDNode *LN0 = cast<LoadSDNode>(N0);
EVT MemVT = LN0->getMemoryVT();
// If we zero all the possible extended bits, then we can turn this into
// a zextload if we are running before legalize or the operation is legal.
unsigned BitWidth = N1.getValueType().getScalarType().getSizeInBits();
if (DAG.MaskedValueIsZero(N1, APInt::getHighBitsSet(BitWidth,
BitWidth - MemVT.getScalarType().getSizeInBits())) &&
((!LegalOperations && !LN0->isVolatile()) ||
TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT))) {
SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, N0.getDebugLoc(), VT,
LN0->getChain(),
LN0->getBasePtr(), LN0->getPointerInfo(),
MemVT,
LN0->isVolatile(), LN0->isNonTemporal(),
LN0->getAlignment());
AddToWorkList(N);
CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1));
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
}
// fold (and (load x), 255) -> (zextload x, i8)
// fold (and (extload x, i16), 255) -> (zextload x, i8)
// fold (and (any_ext (extload x, i16)), 255) -> (zextload x, i8)
if (N1C && (N0.getOpcode() == ISD::LOAD ||
(N0.getOpcode() == ISD::ANY_EXTEND &&
N0.getOperand(0).getOpcode() == ISD::LOAD))) {
bool HasAnyExt = N0.getOpcode() == ISD::ANY_EXTEND;
LoadSDNode *LN0 = HasAnyExt
? cast<LoadSDNode>(N0.getOperand(0))
: cast<LoadSDNode>(N0);
if (LN0->getExtensionType() != ISD::SEXTLOAD &&
LN0->isUnindexed() && N0.hasOneUse() && LN0->hasOneUse()) {
uint32_t ActiveBits = N1C->getAPIntValue().getActiveBits();
if (ActiveBits > 0 && APIntOps::isMask(ActiveBits, N1C->getAPIntValue())){
EVT ExtVT = EVT::getIntegerVT(*DAG.getContext(), ActiveBits);
EVT LoadedVT = LN0->getMemoryVT();
if (ExtVT == LoadedVT &&
(!LegalOperations || TLI.isLoadExtLegal(ISD::ZEXTLOAD, ExtVT))) {
EVT LoadResultTy = HasAnyExt ? LN0->getValueType(0) : VT;
SDValue NewLoad =
DAG.getExtLoad(ISD::ZEXTLOAD, LN0->getDebugLoc(), LoadResultTy,
LN0->getChain(), LN0->getBasePtr(),
LN0->getPointerInfo(),
ExtVT, LN0->isVolatile(), LN0->isNonTemporal(),
LN0->getAlignment());
AddToWorkList(N);
CombineTo(LN0, NewLoad, NewLoad.getValue(1));
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
// Do not change the width of a volatile load.
// Do not generate loads of non-round integer types since these can
// be expensive (and would be wrong if the type is not byte sized).
if (!LN0->isVolatile() && LoadedVT.bitsGT(ExtVT) && ExtVT.isRound() &&
(!LegalOperations || TLI.isLoadExtLegal(ISD::ZEXTLOAD, ExtVT))) {
EVT PtrType = LN0->getOperand(1).getValueType();
unsigned Alignment = LN0->getAlignment();
SDValue NewPtr = LN0->getBasePtr();
// For big endian targets, we need to add an offset to the pointer
// to load the correct bytes. For little endian systems, we merely
// need to read fewer bytes from the same pointer.
if (TLI.isBigEndian()) {
unsigned LVTStoreBytes = LoadedVT.getStoreSize();
unsigned EVTStoreBytes = ExtVT.getStoreSize();
unsigned PtrOff = LVTStoreBytes - EVTStoreBytes;
NewPtr = DAG.getNode(ISD::ADD, LN0->getDebugLoc(), PtrType,
NewPtr, DAG.getConstant(PtrOff, PtrType));
Alignment = MinAlign(Alignment, PtrOff);
}
AddToWorkList(NewPtr.getNode());
EVT LoadResultTy = HasAnyExt ? LN0->getValueType(0) : VT;
SDValue Load =
DAG.getExtLoad(ISD::ZEXTLOAD, LN0->getDebugLoc(), LoadResultTy,
LN0->getChain(), NewPtr,
LN0->getPointerInfo(),
ExtVT, LN0->isVolatile(), LN0->isNonTemporal(),
Alignment);
AddToWorkList(N);
CombineTo(LN0, Load, Load.getValue(1));
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
}
}
}
return SDValue();
}
/// MatchBSwapHWord - Match (a >> 8) | (a << 8) as (bswap a) >> 16
///
SDValue DAGCombiner::MatchBSwapHWordLow(SDNode *N, SDValue N0, SDValue N1,
bool DemandHighBits) {
if (!LegalOperations)
return SDValue();
EVT VT = N->getValueType(0);
if (VT != MVT::i64 && VT != MVT::i32 && VT != MVT::i16)
return SDValue();
if (!TLI.isOperationLegal(ISD::BSWAP, VT))
return SDValue();
// Recognize (and (shl a, 8), 0xff), (and (srl a, 8), 0xff00)
bool LookPassAnd0 = false;
bool LookPassAnd1 = false;
if (N0.getOpcode() == ISD::AND && N0.getOperand(0).getOpcode() == ISD::SRL)
std::swap(N0, N1);
if (N1.getOpcode() == ISD::AND && N1.getOperand(0).getOpcode() == ISD::SHL)
std::swap(N0, N1);
if (N0.getOpcode() == ISD::AND) {
if (!N0.getNode()->hasOneUse())
return SDValue();
ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
if (!N01C || N01C->getZExtValue() != 0xFF00)
return SDValue();
N0 = N0.getOperand(0);
LookPassAnd0 = true;
}
if (N1.getOpcode() == ISD::AND) {
if (!N1.getNode()->hasOneUse())
return SDValue();
ConstantSDNode *N11C = dyn_cast<ConstantSDNode>(N1.getOperand(1));
if (!N11C || N11C->getZExtValue() != 0xFF)
return SDValue();
N1 = N1.getOperand(0);
LookPassAnd1 = true;
}
if (N0.getOpcode() == ISD::SRL && N1.getOpcode() == ISD::SHL)
std::swap(N0, N1);
if (N0.getOpcode() != ISD::SHL || N1.getOpcode() != ISD::SRL)
return SDValue();
if (!N0.getNode()->hasOneUse() ||
!N1.getNode()->hasOneUse())
return SDValue();
ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
ConstantSDNode *N11C = dyn_cast<ConstantSDNode>(N1.getOperand(1));
if (!N01C || !N11C)
return SDValue();
if (N01C->getZExtValue() != 8 || N11C->getZExtValue() != 8)
return SDValue();
// Look for (shl (and a, 0xff), 8), (srl (and a, 0xff00), 8)
SDValue N00 = N0->getOperand(0);
if (!LookPassAnd0 && N00.getOpcode() == ISD::AND) {
if (!N00.getNode()->hasOneUse())
return SDValue();
ConstantSDNode *N001C = dyn_cast<ConstantSDNode>(N00.getOperand(1));
if (!N001C || N001C->getZExtValue() != 0xFF)
return SDValue();
N00 = N00.getOperand(0);
LookPassAnd0 = true;
}
SDValue N10 = N1->getOperand(0);
if (!LookPassAnd1 && N10.getOpcode() == ISD::AND) {
if (!N10.getNode()->hasOneUse())
return SDValue();
ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N10.getOperand(1));
if (!N101C || N101C->getZExtValue() != 0xFF00)
return SDValue();
N10 = N10.getOperand(0);
LookPassAnd1 = true;
}
if (N00 != N10)
return SDValue();
// Make sure everything beyond the low halfword is zero since the SRL 16
// will clear the top bits.
unsigned OpSizeInBits = VT.getSizeInBits();
if (DemandHighBits && OpSizeInBits > 16 &&
(!LookPassAnd0 || !LookPassAnd1) &&
!DAG.MaskedValueIsZero(N10, APInt::getHighBitsSet(OpSizeInBits, 16)))
return SDValue();
SDValue Res = DAG.getNode(ISD::BSWAP, N->getDebugLoc(), VT, N00);
if (OpSizeInBits > 16)
Res = DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, Res,
DAG.getConstant(OpSizeInBits-16, getShiftAmountTy(VT)));
return Res;
}
/// isBSwapHWordElement - Return true if the specified node is an element
/// that makes up a 32-bit packed halfword byteswap. i.e.
/// ((x&0xff)<<8)|((x&0xff00)>>8)|((x&0x00ff0000)<<8)|((x&0xff000000)>>8)
static bool isBSwapHWordElement(SDValue N, SmallVector<SDNode*,4> &Parts) {
if (!N.getNode()->hasOneUse())
return false;
unsigned Opc = N.getOpcode();
if (Opc != ISD::AND && Opc != ISD::SHL && Opc != ISD::SRL)
return false;
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N.getOperand(1));
if (!N1C)
return false;
unsigned Num;
switch (N1C->getZExtValue()) {
default:
return false;
case 0xFF: Num = 0; break;
case 0xFF00: Num = 1; break;
case 0xFF0000: Num = 2; break;
case 0xFF000000: Num = 3; break;
}
// Look for (x & 0xff) << 8 as well as ((x << 8) & 0xff00).
SDValue N0 = N.getOperand(0);
if (Opc == ISD::AND) {
if (Num == 0 || Num == 2) {
// (x >> 8) & 0xff
// (x >> 8) & 0xff0000
if (N0.getOpcode() != ISD::SRL)
return false;
ConstantSDNode *C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
if (!C || C->getZExtValue() != 8)
return false;
} else {
// (x << 8) & 0xff00
// (x << 8) & 0xff000000
if (N0.getOpcode() != ISD::SHL)
return false;
ConstantSDNode *C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
if (!C || C->getZExtValue() != 8)
return false;
}
} else if (Opc == ISD::SHL) {
// (x & 0xff) << 8
// (x & 0xff0000) << 8
if (Num != 0 && Num != 2)
return false;
ConstantSDNode *C = dyn_cast<ConstantSDNode>(N.getOperand(1));
if (!C || C->getZExtValue() != 8)
return false;
} else { // Opc == ISD::SRL
// (x & 0xff00) >> 8
// (x & 0xff000000) >> 8
if (Num != 1 && Num != 3)
return false;
ConstantSDNode *C = dyn_cast<ConstantSDNode>(N.getOperand(1));
if (!C || C->getZExtValue() != 8)
return false;
}
if (Parts[Num])
return false;
Parts[Num] = N0.getOperand(0).getNode();
return true;
}
/// MatchBSwapHWord - Match a 32-bit packed halfword bswap. That is
/// ((x&0xff)<<8)|((x&0xff00)>>8)|((x&0x00ff0000)<<8)|((x&0xff000000)>>8)
/// => (rotl (bswap x), 16)
SDValue DAGCombiner::MatchBSwapHWord(SDNode *N, SDValue N0, SDValue N1) {
if (!LegalOperations)
return SDValue();
EVT VT = N->getValueType(0);
if (VT != MVT::i32)
return SDValue();
if (!TLI.isOperationLegal(ISD::BSWAP, VT))
return SDValue();
SmallVector<SDNode*,4> Parts(4, (SDNode*)0);
// Look for either
// (or (or (and), (and)), (or (and), (and)))
// (or (or (or (and), (and)), (and)), (and))
if (N0.getOpcode() != ISD::OR)
return SDValue();
SDValue N00 = N0.getOperand(0);
SDValue N01 = N0.getOperand(1);
if (N1.getOpcode() == ISD::OR) {
// (or (or (and), (and)), (or (and), (and)))
SDValue N000 = N00.getOperand(0);
if (!isBSwapHWordElement(N000, Parts))
return SDValue();
SDValue N001 = N00.getOperand(1);
if (!isBSwapHWordElement(N001, Parts))
return SDValue();
SDValue N010 = N01.getOperand(0);
if (!isBSwapHWordElement(N010, Parts))
return SDValue();
SDValue N011 = N01.getOperand(1);
if (!isBSwapHWordElement(N011, Parts))
return SDValue();
} else {
// (or (or (or (and), (and)), (and)), (and))
if (!isBSwapHWordElement(N1, Parts))
return SDValue();
if (!isBSwapHWordElement(N01, Parts))
return SDValue();
if (N00.getOpcode() != ISD::OR)
return SDValue();
SDValue N000 = N00.getOperand(0);
if (!isBSwapHWordElement(N000, Parts))
return SDValue();
SDValue N001 = N00.getOperand(1);
if (!isBSwapHWordElement(N001, Parts))
return SDValue();
}
// Make sure the parts are all coming from the same node.
if (Parts[0] != Parts[1] || Parts[0] != Parts[2] || Parts[0] != Parts[3])
return SDValue();
SDValue BSwap = DAG.getNode(ISD::BSWAP, N->getDebugLoc(), VT,
SDValue(Parts[0],0));
// Result of the bswap should be rotated by 16. If it's not legal, than
// do (x << 16) | (x >> 16).
SDValue ShAmt = DAG.getConstant(16, getShiftAmountTy(VT));
if (TLI.isOperationLegalOrCustom(ISD::ROTL, VT))
return DAG.getNode(ISD::ROTL, N->getDebugLoc(), VT, BSwap, ShAmt);
else if (TLI.isOperationLegalOrCustom(ISD::ROTR, VT))
return DAG.getNode(ISD::ROTR, N->getDebugLoc(), VT, BSwap, ShAmt);
return DAG.getNode(ISD::OR, N->getDebugLoc(), VT,
DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, BSwap, ShAmt),
DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, BSwap, ShAmt));
}
SDValue DAGCombiner::visitOR(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
SDValue LL, LR, RL, RR, CC0, CC1;
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
EVT VT = N1.getValueType();
// fold vector ops
if (VT.isVector()) {
SDValue FoldedVOp = SimplifyVBinOp(N);
if (FoldedVOp.getNode()) return FoldedVOp;
}
// fold (or x, undef) -> -1
if (!LegalOperations &&
(N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)) {
EVT EltVT = VT.isVector() ? VT.getVectorElementType() : VT;
return DAG.getConstant(APInt::getAllOnesValue(EltVT.getSizeInBits()), VT);
}
// fold (or c1, c2) -> c1|c2
if (N0C && N1C)
return DAG.FoldConstantArithmetic(ISD::OR, VT, N0C, N1C);
// canonicalize constant to RHS
if (N0C && !N1C)
return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N1, N0);
// fold (or x, 0) -> x
if (N1C && N1C->isNullValue())
return N0;
// fold (or x, -1) -> -1
if (N1C && N1C->isAllOnesValue())
return N1;
// fold (or x, c) -> c iff (x & ~c) == 0
if (N1C && DAG.MaskedValueIsZero(N0, ~N1C->getAPIntValue()))
return N1;
// Recognize halfword bswaps as (bswap + rotl 16) or (bswap + shl 16)
SDValue BSwap = MatchBSwapHWord(N, N0, N1);
if (BSwap.getNode() != 0)
return BSwap;
BSwap = MatchBSwapHWordLow(N, N0, N1);
if (BSwap.getNode() != 0)
return BSwap;
// reassociate or
SDValue ROR = ReassociateOps(ISD::OR, N->getDebugLoc(), N0, N1);
if (ROR.getNode() != 0)
return ROR;
// Canonicalize (or (and X, c1), c2) -> (and (or X, c2), c1|c2)
// iff (c1 & c2) == 0.
if (N1C && N0.getOpcode() == ISD::AND && N0.getNode()->hasOneUse() &&
isa<ConstantSDNode>(N0.getOperand(1))) {
ConstantSDNode *C1 = cast<ConstantSDNode>(N0.getOperand(1));
if ((C1->getAPIntValue() & N1C->getAPIntValue()) != 0)
return DAG.getNode(ISD::AND, N->getDebugLoc(), VT,
DAG.getNode(ISD::OR, N0.getDebugLoc(), VT,
N0.getOperand(0), N1),
DAG.FoldConstantArithmetic(ISD::OR, VT, N1C, C1));
}
// fold (or (setcc x), (setcc y)) -> (setcc (or x, y))
if (isSetCCEquivalent(N0, LL, LR, CC0) && isSetCCEquivalent(N1, RL, RR, CC1)){
ISD::CondCode Op0 = cast<CondCodeSDNode>(CC0)->get();
ISD::CondCode Op1 = cast<CondCodeSDNode>(CC1)->get();
if (LR == RR && isa<ConstantSDNode>(LR) && Op0 == Op1 &&
LL.getValueType().isInteger()) {
// fold (or (setne X, 0), (setne Y, 0)) -> (setne (or X, Y), 0)
// fold (or (setlt X, 0), (setlt Y, 0)) -> (setne (or X, Y), 0)
if (cast<ConstantSDNode>(LR)->isNullValue() &&
(Op1 == ISD::SETNE || Op1 == ISD::SETLT)) {
SDValue ORNode = DAG.getNode(ISD::OR, LR.getDebugLoc(),
LR.getValueType(), LL, RL);
AddToWorkList(ORNode.getNode());
return DAG.getSetCC(N->getDebugLoc(), VT, ORNode, LR, Op1);
}
// fold (or (setne X, -1), (setne Y, -1)) -> (setne (and X, Y), -1)
// fold (or (setgt X, -1), (setgt Y -1)) -> (setgt (and X, Y), -1)
if (cast<ConstantSDNode>(LR)->isAllOnesValue() &&
(Op1 == ISD::SETNE || Op1 == ISD::SETGT)) {
SDValue ANDNode = DAG.getNode(ISD::AND, LR.getDebugLoc(),
LR.getValueType(), LL, RL);
AddToWorkList(ANDNode.getNode());
return DAG.getSetCC(N->getDebugLoc(), VT, ANDNode, LR, Op1);
}
}
// canonicalize equivalent to ll == rl
if (LL == RR && LR == RL) {
Op1 = ISD::getSetCCSwappedOperands(Op1);
std::swap(RL, RR);
}
if (LL == RL && LR == RR) {
bool isInteger = LL.getValueType().isInteger();
ISD::CondCode Result = ISD::getSetCCOrOperation(Op0, Op1, isInteger);
if (Result != ISD::SETCC_INVALID &&
(!LegalOperations || TLI.isCondCodeLegal(Result, LL.getValueType())))
return DAG.getSetCC(N->getDebugLoc(), N0.getValueType(),
LL, LR, Result);
}
}
// Simplify: (or (op x...), (op y...)) -> (op (or x, y))
if (N0.getOpcode() == N1.getOpcode()) {
SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N);
if (Tmp.getNode()) return Tmp;
}
// (or (and X, C1), (and Y, C2)) -> (and (or X, Y), C3) if possible.
if (N0.getOpcode() == ISD::AND &&
N1.getOpcode() == ISD::AND &&
N0.getOperand(1).getOpcode() == ISD::Constant &&
N1.getOperand(1).getOpcode() == ISD::Constant &&
// Don't increase # computations.
(N0.getNode()->hasOneUse() || N1.getNode()->hasOneUse())) {
// We can only do this xform if we know that bits from X that are set in C2
// but not in C1 are already zero. Likewise for Y.
const APInt &LHSMask =
cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
const APInt &RHSMask =
cast<ConstantSDNode>(N1.getOperand(1))->getAPIntValue();
if (DAG.MaskedValueIsZero(N0.getOperand(0), RHSMask&~LHSMask) &&
DAG.MaskedValueIsZero(N1.getOperand(0), LHSMask&~RHSMask)) {
SDValue X = DAG.getNode(ISD::OR, N0.getDebugLoc(), VT,
N0.getOperand(0), N1.getOperand(0));
return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, X,
DAG.getConstant(LHSMask | RHSMask, VT));
}
}
// See if this is some rotate idiom.
if (SDNode *Rot = MatchRotate(N0, N1, N->getDebugLoc()))
return SDValue(Rot, 0);
// Simplify the operands using demanded-bits information.
if (!VT.isVector() &&
SimplifyDemandedBits(SDValue(N, 0)))
return SDValue(N, 0);
return SDValue();
}
/// MatchRotateHalf - Match "(X shl/srl V1) & V2" where V2 may not be present.
static bool MatchRotateHalf(SDValue Op, SDValue &Shift, SDValue &Mask) {
if (Op.getOpcode() == ISD::AND) {
if (isa<ConstantSDNode>(Op.getOperand(1))) {
Mask = Op.getOperand(1);
Op = Op.getOperand(0);
} else {
return false;
}
}
if (Op.getOpcode() == ISD::SRL || Op.getOpcode() == ISD::SHL) {
Shift = Op;
return true;
}
return false;
}
// MatchRotate - Handle an 'or' of two operands. If this is one of the many
// idioms for rotate, and if the target supports rotation instructions, generate
// a rot[lr].
SDNode *DAGCombiner::MatchRotate(SDValue LHS, SDValue RHS, DebugLoc DL) {
// Must be a legal type. Expanded 'n promoted things won't work with rotates.
EVT VT = LHS.getValueType();
if (!TLI.isTypeLegal(VT)) return 0;
// The target must have at least one rotate flavor.
bool HasROTL = TLI.isOperationLegalOrCustom(ISD::ROTL, VT);
bool HasROTR = TLI.isOperationLegalOrCustom(ISD::ROTR, VT);
if (!HasROTL && !HasROTR) return 0;
// Match "(X shl/srl V1) & V2" where V2 may not be present.
SDValue LHSShift; // The shift.
SDValue LHSMask; // AND value if any.
if (!MatchRotateHalf(LHS, LHSShift, LHSMask))
return 0; // Not part of a rotate.
SDValue RHSShift; // The shift.
SDValue RHSMask; // AND value if any.
if (!MatchRotateHalf(RHS, RHSShift, RHSMask))
return 0; // Not part of a rotate.
if (LHSShift.getOperand(0) != RHSShift.getOperand(0))
return 0; // Not shifting the same value.
if (LHSShift.getOpcode() == RHSShift.getOpcode())
return 0; // Shifts must disagree.
// Canonicalize shl to left side in a shl/srl pair.
if (RHSShift.getOpcode() == ISD::SHL) {
std::swap(LHS, RHS);
std::swap(LHSShift, RHSShift);
std::swap(LHSMask , RHSMask );
}
unsigned OpSizeInBits = VT.getSizeInBits();
SDValue LHSShiftArg = LHSShift.getOperand(0);
SDValue LHSShiftAmt = LHSShift.getOperand(1);
SDValue RHSShiftAmt = RHSShift.getOperand(1);
// fold (or (shl x, C1), (srl x, C2)) -> (rotl x, C1)
// fold (or (shl x, C1), (srl x, C2)) -> (rotr x, C2)
if (LHSShiftAmt.getOpcode() == ISD::Constant &&
RHSShiftAmt.getOpcode() == ISD::Constant) {
uint64_t LShVal = cast<ConstantSDNode>(LHSShiftAmt)->getZExtValue();
uint64_t RShVal = cast<ConstantSDNode>(RHSShiftAmt)->getZExtValue();
if ((LShVal + RShVal) != OpSizeInBits)
return 0;
SDValue Rot;
if (HasROTL)
Rot = DAG.getNode(ISD::ROTL, DL, VT, LHSShiftArg, LHSShiftAmt);
else
Rot = DAG.getNode(ISD::ROTR, DL, VT, LHSShiftArg, RHSShiftAmt);
// If there is an AND of either shifted operand, apply it to the result.
if (LHSMask.getNode() || RHSMask.getNode()) {
APInt Mask = APInt::getAllOnesValue(OpSizeInBits);
if (LHSMask.getNode()) {
APInt RHSBits = APInt::getLowBitsSet(OpSizeInBits, LShVal);
Mask &= cast<ConstantSDNode>(LHSMask)->getAPIntValue() | RHSBits;
}
if (RHSMask.getNode()) {
APInt LHSBits = APInt::getHighBitsSet(OpSizeInBits, RShVal);
Mask &= cast<ConstantSDNode>(RHSMask)->getAPIntValue() | LHSBits;
}
Rot = DAG.getNode(ISD::AND, DL, VT, Rot, DAG.getConstant(Mask, VT));
}
return Rot.getNode();
}
// If there is a mask here, and we have a variable shift, we can't be sure
// that we're masking out the right stuff.
if (LHSMask.getNode() || RHSMask.getNode())
return 0;
// fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotl x, y)
// fold (or (shl x, y), (srl x, (sub 32, y))) -> (rotr x, (sub 32, y))
if (RHSShiftAmt.getOpcode() == ISD::SUB &&
LHSShiftAmt == RHSShiftAmt.getOperand(1)) {
if (ConstantSDNode *SUBC =
dyn_cast<ConstantSDNode>(RHSShiftAmt.getOperand(0))) {
if (SUBC->getAPIntValue() == OpSizeInBits) {
if (HasROTL)
return DAG.getNode(ISD::ROTL, DL, VT,
LHSShiftArg, LHSShiftAmt).getNode();
else
return DAG.getNode(ISD::ROTR, DL, VT,
LHSShiftArg, RHSShiftAmt).getNode();
}
}
}
// fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotr x, y)
// fold (or (shl x, (sub 32, y)), (srl x, r)) -> (rotl x, (sub 32, y))
if (LHSShiftAmt.getOpcode() == ISD::SUB &&
RHSShiftAmt == LHSShiftAmt.getOperand(1)) {
if (ConstantSDNode *SUBC =
dyn_cast<ConstantSDNode>(LHSShiftAmt.getOperand(0))) {
if (SUBC->getAPIntValue() == OpSizeInBits) {
if (HasROTR)
return DAG.getNode(ISD::ROTR, DL, VT,
LHSShiftArg, RHSShiftAmt).getNode();
else
return DAG.getNode(ISD::ROTL, DL, VT,
LHSShiftArg, LHSShiftAmt).getNode();
}
}
}
// Look for sign/zext/any-extended or truncate cases:
if ((LHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND
|| LHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND
|| LHSShiftAmt.getOpcode() == ISD::ANY_EXTEND
|| LHSShiftAmt.getOpcode() == ISD::TRUNCATE) &&
(RHSShiftAmt.getOpcode() == ISD::SIGN_EXTEND
|| RHSShiftAmt.getOpcode() == ISD::ZERO_EXTEND
|| RHSShiftAmt.getOpcode() == ISD::ANY_EXTEND
|| RHSShiftAmt.getOpcode() == ISD::TRUNCATE)) {
SDValue LExtOp0 = LHSShiftAmt.getOperand(0);
SDValue RExtOp0 = RHSShiftAmt.getOperand(0);
if (RExtOp0.getOpcode() == ISD::SUB &&
RExtOp0.getOperand(1) == LExtOp0) {
// fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) ->
// (rotl x, y)
// fold (or (shl x, (*ext y)), (srl x, (*ext (sub 32, y)))) ->
// (rotr x, (sub 32, y))
if (ConstantSDNode *SUBC =
dyn_cast<ConstantSDNode>(RExtOp0.getOperand(0))) {
if (SUBC->getAPIntValue() == OpSizeInBits) {
return DAG.getNode(HasROTL ? ISD::ROTL : ISD::ROTR, DL, VT,
LHSShiftArg,
HasROTL ? LHSShiftAmt : RHSShiftAmt).getNode();
}
}
} else if (LExtOp0.getOpcode() == ISD::SUB &&
RExtOp0 == LExtOp0.getOperand(1)) {
// fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext y))) ->
// (rotr x, y)
// fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext y))) ->
// (rotl x, (sub 32, y))
if (ConstantSDNode *SUBC =
dyn_cast<ConstantSDNode>(LExtOp0.getOperand(0))) {
if (SUBC->getAPIntValue() == OpSizeInBits) {
return DAG.getNode(HasROTR ? ISD::ROTR : ISD::ROTL, DL, VT,
LHSShiftArg,
HasROTR ? RHSShiftAmt : LHSShiftAmt).getNode();
}
}
}
}
return 0;
}
SDValue DAGCombiner::visitXOR(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
SDValue LHS, RHS, CC;
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
EVT VT = N0.getValueType();
// fold vector ops
if (VT.isVector()) {
SDValue FoldedVOp = SimplifyVBinOp(N);
if (FoldedVOp.getNode()) return FoldedVOp;
}
// fold (xor undef, undef) -> 0. This is a common idiom (misuse).
if (N0.getOpcode() == ISD::UNDEF && N1.getOpcode() == ISD::UNDEF)
return DAG.getConstant(0, VT);
// fold (xor x, undef) -> undef
if (N0.getOpcode() == ISD::UNDEF)
return N0;
if (N1.getOpcode() == ISD::UNDEF)
return N1;
// fold (xor c1, c2) -> c1^c2
if (N0C && N1C)
return DAG.FoldConstantArithmetic(ISD::XOR, VT, N0C, N1C);
// canonicalize constant to RHS
if (N0C && !N1C)
return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N1, N0);
// fold (xor x, 0) -> x
if (N1C && N1C->isNullValue())
return N0;
// reassociate xor
SDValue RXOR = ReassociateOps(ISD::XOR, N->getDebugLoc(), N0, N1);
if (RXOR.getNode() != 0)
return RXOR;
// fold !(x cc y) -> (x !cc y)
if (N1C && N1C->getAPIntValue() == 1 && isSetCCEquivalent(N0, LHS, RHS, CC)) {
bool isInt = LHS.getValueType().isInteger();
ISD::CondCode NotCC = ISD::getSetCCInverse(cast<CondCodeSDNode>(CC)->get(),
isInt);
if (!LegalOperations || TLI.isCondCodeLegal(NotCC, LHS.getValueType())) {
switch (N0.getOpcode()) {
default:
llvm_unreachable("Unhandled SetCC Equivalent!");
case ISD::SETCC:
return DAG.getSetCC(N->getDebugLoc(), VT, LHS, RHS, NotCC);
case ISD::SELECT_CC:
return DAG.getSelectCC(N->getDebugLoc(), LHS, RHS, N0.getOperand(2),
N0.getOperand(3), NotCC);
}
}
}
// fold (not (zext (setcc x, y))) -> (zext (not (setcc x, y)))
if (N1C && N1C->getAPIntValue() == 1 && N0.getOpcode() == ISD::ZERO_EXTEND &&
N0.getNode()->hasOneUse() &&
isSetCCEquivalent(N0.getOperand(0), LHS, RHS, CC)){
SDValue V = N0.getOperand(0);
V = DAG.getNode(ISD::XOR, N0.getDebugLoc(), V.getValueType(), V,
DAG.getConstant(1, V.getValueType()));
AddToWorkList(V.getNode());
return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, V);
}
// fold (not (or x, y)) -> (and (not x), (not y)) iff x or y are setcc
if (N1C && N1C->getAPIntValue() == 1 && VT == MVT::i1 &&
(N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) {
SDValue LHS = N0.getOperand(0), RHS = N0.getOperand(1);
if (isOneUseSetCC(RHS) || isOneUseSetCC(LHS)) {
unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND;
LHS = DAG.getNode(ISD::XOR, LHS.getDebugLoc(), VT, LHS, N1); // LHS = ~LHS
RHS = DAG.getNode(ISD::XOR, RHS.getDebugLoc(), VT, RHS, N1); // RHS = ~RHS
AddToWorkList(LHS.getNode()); AddToWorkList(RHS.getNode());
return DAG.getNode(NewOpcode, N->getDebugLoc(), VT, LHS, RHS);
}
}
// fold (not (or x, y)) -> (and (not x), (not y)) iff x or y are constants
if (N1C && N1C->isAllOnesValue() &&
(N0.getOpcode() == ISD::OR || N0.getOpcode() == ISD::AND)) {
SDValue LHS = N0.getOperand(0), RHS = N0.getOperand(1);
if (isa<ConstantSDNode>(RHS) || isa<ConstantSDNode>(LHS)) {
unsigned NewOpcode = N0.getOpcode() == ISD::AND ? ISD::OR : ISD::AND;
LHS = DAG.getNode(ISD::XOR, LHS.getDebugLoc(), VT, LHS, N1); // LHS = ~LHS
RHS = DAG.getNode(ISD::XOR, RHS.getDebugLoc(), VT, RHS, N1); // RHS = ~RHS
AddToWorkList(LHS.getNode()); AddToWorkList(RHS.getNode());
return DAG.getNode(NewOpcode, N->getDebugLoc(), VT, LHS, RHS);
}
}
// fold (xor (xor x, c1), c2) -> (xor x, (xor c1, c2))
if (N1C && N0.getOpcode() == ISD::XOR) {
ConstantSDNode *N00C = dyn_cast<ConstantSDNode>(N0.getOperand(0));
ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
if (N00C)
return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N0.getOperand(1),
DAG.getConstant(N1C->getAPIntValue() ^
N00C->getAPIntValue(), VT));
if (N01C)
return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N0.getOperand(0),
DAG.getConstant(N1C->getAPIntValue() ^
N01C->getAPIntValue(), VT));
}
// fold (xor x, x) -> 0
if (N0 == N1)
return tryFoldToZero(N->getDebugLoc(), TLI, VT, DAG, LegalOperations);
// Simplify: xor (op x...), (op y...) -> (op (xor x, y))
if (N0.getOpcode() == N1.getOpcode()) {
SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N);
if (Tmp.getNode()) return Tmp;
}
// Simplify the expression using non-local knowledge.
if (!VT.isVector() &&
SimplifyDemandedBits(SDValue(N, 0)))
return SDValue(N, 0);
return SDValue();
}
/// visitShiftByConstant - Handle transforms common to the three shifts, when
/// the shift amount is a constant.
SDValue DAGCombiner::visitShiftByConstant(SDNode *N, unsigned Amt) {
SDNode *LHS = N->getOperand(0).getNode();
if (!LHS->hasOneUse()) return SDValue();
// We want to pull some binops through shifts, so that we have (and (shift))
// instead of (shift (and)), likewise for add, or, xor, etc. This sort of
// thing happens with address calculations, so it's important to canonicalize
// it.
bool HighBitSet = false; // Can we transform this if the high bit is set?
switch (LHS->getOpcode()) {
default: return SDValue();
case ISD::OR:
case ISD::XOR:
HighBitSet = false; // We can only transform sra if the high bit is clear.
break;
case ISD::AND:
HighBitSet = true; // We can only transform sra if the high bit is set.
break;
case ISD::ADD:
if (N->getOpcode() != ISD::SHL)
return SDValue(); // only shl(add) not sr[al](add).
HighBitSet = false; // We can only transform sra if the high bit is clear.
break;
}
// We require the RHS of the binop to be a constant as well.
ConstantSDNode *BinOpCst = dyn_cast<ConstantSDNode>(LHS->getOperand(1));
if (!BinOpCst) return SDValue();
// FIXME: disable this unless the input to the binop is a shift by a constant.
// If it is not a shift, it pessimizes some common cases like:
//
// void foo(int *X, int i) { X[i & 1235] = 1; }
// int bar(int *X, int i) { return X[i & 255]; }
SDNode *BinOpLHSVal = LHS->getOperand(0).getNode();
if ((BinOpLHSVal->getOpcode() != ISD::SHL &&
BinOpLHSVal->getOpcode() != ISD::SRA &&
BinOpLHSVal->getOpcode() != ISD::SRL) ||
!isa<ConstantSDNode>(BinOpLHSVal->getOperand(1)))
return SDValue();
EVT VT = N->getValueType(0);
// If this is a signed shift right, and the high bit is modified by the
// logical operation, do not perform the transformation. The highBitSet
// boolean indicates the value of the high bit of the constant which would
// cause it to be modified for this operation.
if (N->getOpcode() == ISD::SRA) {
bool BinOpRHSSignSet = BinOpCst->getAPIntValue().isNegative();
if (BinOpRHSSignSet != HighBitSet)
return SDValue();
}
// Fold the constants, shifting the binop RHS by the shift amount.
SDValue NewRHS = DAG.getNode(N->getOpcode(), LHS->getOperand(1).getDebugLoc(),
N->getValueType(0),
LHS->getOperand(1), N->getOperand(1));
// Create the new shift.
SDValue NewShift = DAG.getNode(N->getOpcode(),
LHS->getOperand(0).getDebugLoc(),
VT, LHS->getOperand(0), N->getOperand(1));
// Create the new binop.
return DAG.getNode(LHS->getOpcode(), N->getDebugLoc(), VT, NewShift, NewRHS);
}
SDValue DAGCombiner::visitSHL(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
EVT VT = N0.getValueType();
unsigned OpSizeInBits = VT.getScalarType().getSizeInBits();
// fold (shl c1, c2) -> c1<<c2
if (N0C && N1C)
return DAG.FoldConstantArithmetic(ISD::SHL, VT, N0C, N1C);
// fold (shl 0, x) -> 0
if (N0C && N0C->isNullValue())
return N0;
// fold (shl x, c >= size(x)) -> undef
if (N1C && N1C->getZExtValue() >= OpSizeInBits)
return DAG.getUNDEF(VT);
// fold (shl x, 0) -> x
if (N1C && N1C->isNullValue())
return N0;
// fold (shl undef, x) -> 0
if (N0.getOpcode() == ISD::UNDEF)
return DAG.getConstant(0, VT);
// if (shl x, c) is known to be zero, return 0
if (DAG.MaskedValueIsZero(SDValue(N, 0),
APInt::getAllOnesValue(OpSizeInBits)))
return DAG.getConstant(0, VT);
// fold (shl x, (trunc (and y, c))) -> (shl x, (and (trunc y), (trunc c))).
if (N1.getOpcode() == ISD::TRUNCATE &&
N1.getOperand(0).getOpcode() == ISD::AND &&
N1.hasOneUse() && N1.getOperand(0).hasOneUse()) {
SDValue N101 = N1.getOperand(0).getOperand(1);
if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) {
EVT TruncVT = N1.getValueType();
SDValue N100 = N1.getOperand(0).getOperand(0);
APInt TruncC = N101C->getAPIntValue();
TruncC = TruncC.trunc(TruncVT.getSizeInBits());
return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0,
DAG.getNode(ISD::AND, N->getDebugLoc(), TruncVT,
DAG.getNode(ISD::TRUNCATE,
N->getDebugLoc(),
TruncVT, N100),
DAG.getConstant(TruncC, TruncVT)));
}
}
if (N1C && SimplifyDemandedBits(SDValue(N, 0)))
return SDValue(N, 0);
// fold (shl (shl x, c1), c2) -> 0 or (shl x, (add c1, c2))
if (N1C && N0.getOpcode() == ISD::SHL &&
N0.getOperand(1).getOpcode() == ISD::Constant) {
uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue();
uint64_t c2 = N1C->getZExtValue();
if (c1 + c2 >= OpSizeInBits)
return DAG.getConstant(0, VT);
return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0.getOperand(0),
DAG.getConstant(c1 + c2, N1.getValueType()));
}
// fold (shl (ext (shl x, c1)), c2) -> (ext (shl x, (add c1, c2)))
// For this to be valid, the second form must not preserve any of the bits
// that are shifted out by the inner shift in the first form. This means
// the outer shift size must be >= the number of bits added by the ext.
// As a corollary, we don't care what kind of ext it is.
if (N1C && (N0.getOpcode() == ISD::ZERO_EXTEND ||
N0.getOpcode() == ISD::ANY_EXTEND ||
N0.getOpcode() == ISD::SIGN_EXTEND) &&
N0.getOperand(0).getOpcode() == ISD::SHL &&
isa<ConstantSDNode>(N0.getOperand(0)->getOperand(1))) {
uint64_t c1 =
cast<ConstantSDNode>(N0.getOperand(0)->getOperand(1))->getZExtValue();
uint64_t c2 = N1C->getZExtValue();
EVT InnerShiftVT = N0.getOperand(0).getValueType();
uint64_t InnerShiftSize = InnerShiftVT.getScalarType().getSizeInBits();
if (c2 >= OpSizeInBits - InnerShiftSize) {
if (c1 + c2 >= OpSizeInBits)
return DAG.getConstant(0, VT);
return DAG.getNode(ISD::SHL, N0->getDebugLoc(), VT,
DAG.getNode(N0.getOpcode(), N0->getDebugLoc(), VT,
N0.getOperand(0)->getOperand(0)),
DAG.getConstant(c1 + c2, N1.getValueType()));
}
}
// fold (shl (srl x, c1), c2) -> (and (shl x, (sub c2, c1), MASK) or
// (and (srl x, (sub c1, c2), MASK)
if (N1C && N0.getOpcode() == ISD::SRL &&
N0.getOperand(1).getOpcode() == ISD::Constant) {
uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue();
if (c1 < VT.getSizeInBits()) {
uint64_t c2 = N1C->getZExtValue();
APInt Mask = APInt::getHighBitsSet(VT.getSizeInBits(),
VT.getSizeInBits() - c1);
SDValue Shift;
if (c2 > c1) {
Mask = Mask.shl(c2-c1);
Shift = DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0.getOperand(0),
DAG.getConstant(c2-c1, N1.getValueType()));
} else {
Mask = Mask.lshr(c1-c2);
Shift = DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0.getOperand(0),
DAG.getConstant(c1-c2, N1.getValueType()));
}
return DAG.getNode(ISD::AND, N0.getDebugLoc(), VT, Shift,
DAG.getConstant(Mask, VT));
}
}
// fold (shl (sra x, c1), c1) -> (and x, (shl -1, c1))
if (N1C && N0.getOpcode() == ISD::SRA && N1 == N0.getOperand(1)) {
SDValue HiBitsMask =
DAG.getConstant(APInt::getHighBitsSet(VT.getSizeInBits(),
VT.getSizeInBits() -
N1C->getZExtValue()),
VT);
return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0.getOperand(0),
HiBitsMask);
}
if (N1C) {
SDValue NewSHL = visitShiftByConstant(N, N1C->getZExtValue());
if (NewSHL.getNode())
return NewSHL;
}
return SDValue();
}
SDValue DAGCombiner::visitSRA(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
EVT VT = N0.getValueType();
unsigned OpSizeInBits = VT.getScalarType().getSizeInBits();
// fold (sra c1, c2) -> (sra c1, c2)
if (N0C && N1C)
return DAG.FoldConstantArithmetic(ISD::SRA, VT, N0C, N1C);
// fold (sra 0, x) -> 0
if (N0C && N0C->isNullValue())
return N0;
// fold (sra -1, x) -> -1
if (N0C && N0C->isAllOnesValue())
return N0;
// fold (sra x, (setge c, size(x))) -> undef
if (N1C && N1C->getZExtValue() >= OpSizeInBits)
return DAG.getUNDEF(VT);
// fold (sra x, 0) -> x
if (N1C && N1C->isNullValue())
return N0;
// fold (sra (shl x, c1), c1) -> sext_inreg for some c1 and target supports
// sext_inreg.
if (N1C && N0.getOpcode() == ISD::SHL && N1 == N0.getOperand(1)) {
unsigned LowBits = OpSizeInBits - (unsigned)N1C->getZExtValue();
EVT ExtVT = EVT::getIntegerVT(*DAG.getContext(), LowBits);
if (VT.isVector())
ExtVT = EVT::getVectorVT(*DAG.getContext(),
ExtVT, VT.getVectorNumElements());
if ((!LegalOperations ||
TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, ExtVT)))
return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT,
N0.getOperand(0), DAG.getValueType(ExtVT));
}
// fold (sra (sra x, c1), c2) -> (sra x, (add c1, c2))
if (N1C && N0.getOpcode() == ISD::SRA) {
if (ConstantSDNode *C1 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
unsigned Sum = N1C->getZExtValue() + C1->getZExtValue();
if (Sum >= OpSizeInBits) Sum = OpSizeInBits-1;
return DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, N0.getOperand(0),
DAG.getConstant(Sum, N1C->getValueType(0)));
}
}
// fold (sra (shl X, m), (sub result_size, n))
// -> (sign_extend (trunc (shl X, (sub (sub result_size, n), m)))) for
// result_size - n != m.
// If truncate is free for the target sext(shl) is likely to result in better
// code.
if (N0.getOpcode() == ISD::SHL) {
// Get the two constanst of the shifts, CN0 = m, CN = n.
const ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
if (N01C && N1C) {
// Determine what the truncate's result bitsize and type would be.
EVT TruncVT =
EVT::getIntegerVT(*DAG.getContext(),
OpSizeInBits - N1C->getZExtValue());
// Determine the residual right-shift amount.
signed ShiftAmt = N1C->getZExtValue() - N01C->getZExtValue();
// If the shift is not a no-op (in which case this should be just a sign
// extend already), the truncated to type is legal, sign_extend is legal
// on that type, and the truncate to that type is both legal and free,
// perform the transform.
if ((ShiftAmt > 0) &&
TLI.isOperationLegalOrCustom(ISD::SIGN_EXTEND, TruncVT) &&
TLI.isOperationLegalOrCustom(ISD::TRUNCATE, VT) &&
TLI.isTruncateFree(VT, TruncVT)) {
SDValue Amt = DAG.getConstant(ShiftAmt,
getShiftAmountTy(N0.getOperand(0).getValueType()));
SDValue Shift = DAG.getNode(ISD::SRL, N0.getDebugLoc(), VT,
N0.getOperand(0), Amt);
SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), TruncVT,
Shift);
return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(),
N->getValueType(0), Trunc);
}
}
}
// fold (sra x, (trunc (and y, c))) -> (sra x, (and (trunc y), (trunc c))).
if (N1.getOpcode() == ISD::TRUNCATE &&
N1.getOperand(0).getOpcode() == ISD::AND &&
N1.hasOneUse() && N1.getOperand(0).hasOneUse()) {
SDValue N101 = N1.getOperand(0).getOperand(1);
if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) {
EVT TruncVT = N1.getValueType();
SDValue N100 = N1.getOperand(0).getOperand(0);
APInt TruncC = N101C->getAPIntValue();
TruncC = TruncC.trunc(TruncVT.getScalarType().getSizeInBits());
return DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, N0,
DAG.getNode(ISD::AND, N->getDebugLoc(),
TruncVT,
DAG.getNode(ISD::TRUNCATE,
N->getDebugLoc(),
TruncVT, N100),
DAG.getConstant(TruncC, TruncVT)));
}
}
// fold (sra (trunc (sr x, c1)), c2) -> (trunc (sra x, c1+c2))
// if c1 is equal to the number of bits the trunc removes
if (N0.getOpcode() == ISD::TRUNCATE &&
(N0.getOperand(0).getOpcode() == ISD::SRL ||
N0.getOperand(0).getOpcode() == ISD::SRA) &&
N0.getOperand(0).hasOneUse() &&
N0.getOperand(0).getOperand(1).hasOneUse() &&
N1C && isa<ConstantSDNode>(N0.getOperand(0).getOperand(1))) {
EVT LargeVT = N0.getOperand(0).getValueType();
ConstantSDNode *LargeShiftAmt =
cast<ConstantSDNode>(N0.getOperand(0).getOperand(1));
if (LargeVT.getScalarType().getSizeInBits() - OpSizeInBits ==
LargeShiftAmt->getZExtValue()) {
SDValue Amt =
DAG.getConstant(LargeShiftAmt->getZExtValue() + N1C->getZExtValue(),
getShiftAmountTy(N0.getOperand(0).getOperand(0).getValueType()));
SDValue SRA = DAG.getNode(ISD::SRA, N->getDebugLoc(), LargeVT,
N0.getOperand(0).getOperand(0), Amt);
return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, SRA);
}
}
// Simplify, based on bits shifted out of the LHS.
if (N1C && SimplifyDemandedBits(SDValue(N, 0)))
return SDValue(N, 0);
// If the sign bit is known to be zero, switch this to a SRL.
if (DAG.SignBitIsZero(N0))
return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0, N1);
if (N1C) {
SDValue NewSRA = visitShiftByConstant(N, N1C->getZExtValue());
if (NewSRA.getNode())
return NewSRA;
}
return SDValue();
}
SDValue DAGCombiner::visitSRL(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
EVT VT = N0.getValueType();
unsigned OpSizeInBits = VT.getScalarType().getSizeInBits();
// fold (srl c1, c2) -> c1 >>u c2
if (N0C && N1C)
return DAG.FoldConstantArithmetic(ISD::SRL, VT, N0C, N1C);
// fold (srl 0, x) -> 0
if (N0C && N0C->isNullValue())
return N0;
// fold (srl x, c >= size(x)) -> undef
if (N1C && N1C->getZExtValue() >= OpSizeInBits)
return DAG.getUNDEF(VT);
// fold (srl x, 0) -> x
if (N1C && N1C->isNullValue())
return N0;
// if (srl x, c) is known to be zero, return 0
if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0),
APInt::getAllOnesValue(OpSizeInBits)))
return DAG.getConstant(0, VT);
// fold (srl (srl x, c1), c2) -> 0 or (srl x, (add c1, c2))
if (N1C && N0.getOpcode() == ISD::SRL &&
N0.getOperand(1).getOpcode() == ISD::Constant) {
uint64_t c1 = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue();
uint64_t c2 = N1C->getZExtValue();
if (c1 + c2 >= OpSizeInBits)
return DAG.getConstant(0, VT);
return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0.getOperand(0),
DAG.getConstant(c1 + c2, N1.getValueType()));
}
// fold (srl (trunc (srl x, c1)), c2) -> 0 or (trunc (srl x, (add c1, c2)))
if (N1C && N0.getOpcode() == ISD::TRUNCATE &&
N0.getOperand(0).getOpcode() == ISD::SRL &&
isa<ConstantSDNode>(N0.getOperand(0)->getOperand(1))) {
uint64_t c1 =
cast<ConstantSDNode>(N0.getOperand(0)->getOperand(1))->getZExtValue();
uint64_t c2 = N1C->getZExtValue();
EVT InnerShiftVT = N0.getOperand(0).getValueType();
EVT ShiftCountVT = N0.getOperand(0)->getOperand(1).getValueType();
uint64_t InnerShiftSize = InnerShiftVT.getScalarType().getSizeInBits();
// This is only valid if the OpSizeInBits + c1 = size of inner shift.
if (c1 + OpSizeInBits == InnerShiftSize) {
if (c1 + c2 >= InnerShiftSize)
return DAG.getConstant(0, VT);
return DAG.getNode(ISD::TRUNCATE, N0->getDebugLoc(), VT,
DAG.getNode(ISD::SRL, N0->getDebugLoc(), InnerShiftVT,
N0.getOperand(0)->getOperand(0),
DAG.getConstant(c1 + c2, ShiftCountVT)));
}
}
// fold (srl (shl x, c), c) -> (and x, cst2)
if (N1C && N0.getOpcode() == ISD::SHL && N0.getOperand(1) == N1 &&
N0.getValueSizeInBits() <= 64) {
uint64_t ShAmt = N1C->getZExtValue()+64-N0.getValueSizeInBits();
return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0.getOperand(0),
DAG.getConstant(~0ULL >> ShAmt, VT));
}
// fold (srl (anyextend x), c) -> (anyextend (srl x, c))
if (N1C && N0.getOpcode() == ISD::ANY_EXTEND) {
// Shifting in all undef bits?
EVT SmallVT = N0.getOperand(0).getValueType();
if (N1C->getZExtValue() >= SmallVT.getSizeInBits())
return DAG.getUNDEF(VT);
if (!LegalTypes || TLI.isTypeDesirableForOp(ISD::SRL, SmallVT)) {
uint64_t ShiftAmt = N1C->getZExtValue();
SDValue SmallShift = DAG.getNode(ISD::SRL, N0.getDebugLoc(), SmallVT,
N0.getOperand(0),
DAG.getConstant(ShiftAmt, getShiftAmountTy(SmallVT)));
AddToWorkList(SmallShift.getNode());
return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, SmallShift);
}
}
// fold (srl (sra X, Y), 31) -> (srl X, 31). This srl only looks at the sign
// bit, which is unmodified by sra.
if (N1C && N1C->getZExtValue() + 1 == VT.getSizeInBits()) {
if (N0.getOpcode() == ISD::SRA)
return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0.getOperand(0), N1);
}
// fold (srl (ctlz x), "5") -> x iff x has one bit set (the low bit).
if (N1C && N0.getOpcode() == ISD::CTLZ &&
N1C->getAPIntValue() == Log2_32(VT.getSizeInBits())) {
APInt KnownZero, KnownOne;
APInt Mask = APInt::getAllOnesValue(VT.getScalarType().getSizeInBits());
DAG.ComputeMaskedBits(N0.getOperand(0), Mask, KnownZero, KnownOne);
// If any of the input bits are KnownOne, then the input couldn't be all
// zeros, thus the result of the srl will always be zero.
if (KnownOne.getBoolValue()) return DAG.getConstant(0, VT);
// If all of the bits input the to ctlz node are known to be zero, then
// the result of the ctlz is "32" and the result of the shift is one.
APInt UnknownBits = ~KnownZero & Mask;
if (UnknownBits == 0) return DAG.getConstant(1, VT);
// Otherwise, check to see if there is exactly one bit input to the ctlz.
if ((UnknownBits & (UnknownBits - 1)) == 0) {
// Okay, we know that only that the single bit specified by UnknownBits
// could be set on input to the CTLZ node. If this bit is set, the SRL
// will return 0, if it is clear, it returns 1. Change the CTLZ/SRL pair
// to an SRL/XOR pair, which is likely to simplify more.
unsigned ShAmt = UnknownBits.countTrailingZeros();
SDValue Op = N0.getOperand(0);
if (ShAmt) {
Op = DAG.getNode(ISD::SRL, N0.getDebugLoc(), VT, Op,
DAG.getConstant(ShAmt, getShiftAmountTy(Op.getValueType())));
AddToWorkList(Op.getNode());
}
return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT,
Op, DAG.getConstant(1, VT));
}
}
// fold (srl x, (trunc (and y, c))) -> (srl x, (and (trunc y), (trunc c))).
if (N1.getOpcode() == ISD::TRUNCATE &&
N1.getOperand(0).getOpcode() == ISD::AND &&
N1.hasOneUse() && N1.getOperand(0).hasOneUse()) {
SDValue N101 = N1.getOperand(0).getOperand(1);
if (ConstantSDNode *N101C = dyn_cast<ConstantSDNode>(N101)) {
EVT TruncVT = N1.getValueType();
SDValue N100 = N1.getOperand(0).getOperand(0);
APInt TruncC = N101C->getAPIntValue();
TruncC = TruncC.trunc(TruncVT.getSizeInBits());
return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0,
DAG.getNode(ISD::AND, N->getDebugLoc(),
TruncVT,
DAG.getNode(ISD::TRUNCATE,
N->getDebugLoc(),
TruncVT, N100),
DAG.getConstant(TruncC, TruncVT)));
}
}
// fold operands of srl based on knowledge that the low bits are not
// demanded.
if (N1C && SimplifyDemandedBits(SDValue(N, 0)))
return SDValue(N, 0);
if (N1C) {
SDValue NewSRL = visitShiftByConstant(N, N1C->getZExtValue());
if (NewSRL.getNode())
return NewSRL;
}
// Attempt to convert a srl of a load into a narrower zero-extending load.
SDValue NarrowLoad = ReduceLoadWidth(N);
if (NarrowLoad.getNode())
return NarrowLoad;
// Here is a common situation. We want to optimize:
//
// %a = ...
// %b = and i32 %a, 2
// %c = srl i32 %b, 1
// brcond i32 %c ...
//
// into
//
// %a = ...
// %b = and %a, 2
// %c = setcc eq %b, 0
// brcond %c ...
//
// However when after the source operand of SRL is optimized into AND, the SRL
// itself may not be optimized further. Look for it and add the BRCOND into
// the worklist.
if (N->hasOneUse()) {
SDNode *Use = *N->use_begin();
if (Use->getOpcode() == ISD::BRCOND)
AddToWorkList(Use);
else if (Use->getOpcode() == ISD::TRUNCATE && Use->hasOneUse()) {
// Also look pass the truncate.
Use = *Use->use_begin();
if (Use->getOpcode() == ISD::BRCOND)
AddToWorkList(Use);
}
}
return SDValue();
}
SDValue DAGCombiner::visitCTLZ(SDNode *N) {
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
// fold (ctlz c1) -> c2
if (isa<ConstantSDNode>(N0))
return DAG.getNode(ISD::CTLZ, N->getDebugLoc(), VT, N0);
return SDValue();
}
SDValue DAGCombiner::visitCTTZ(SDNode *N) {
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
// fold (cttz c1) -> c2
if (isa<ConstantSDNode>(N0))
return DAG.getNode(ISD::CTTZ, N->getDebugLoc(), VT, N0);
return SDValue();
}
SDValue DAGCombiner::visitCTPOP(SDNode *N) {
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
// fold (ctpop c1) -> c2
if (isa<ConstantSDNode>(N0))
return DAG.getNode(ISD::CTPOP, N->getDebugLoc(), VT, N0);
return SDValue();
}
SDValue DAGCombiner::visitSELECT(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
SDValue N2 = N->getOperand(2);
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2);
EVT VT = N->getValueType(0);
EVT VT0 = N0.getValueType();
// fold (select C, X, X) -> X
if (N1 == N2)
return N1;
// fold (select true, X, Y) -> X
if (N0C && !N0C->isNullValue())
return N1;
// fold (select false, X, Y) -> Y
if (N0C && N0C->isNullValue())
return N2;
// fold (select C, 1, X) -> (or C, X)
if (VT == MVT::i1 && N1C && N1C->getAPIntValue() == 1)
return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N2);
// fold (select C, 0, 1) -> (xor C, 1)
if (VT.isInteger() &&
(VT0 == MVT::i1 ||
(VT0.isInteger() &&
TLI.getBooleanContents(false) == TargetLowering::ZeroOrOneBooleanContent)) &&
N1C && N2C && N1C->isNullValue() && N2C->getAPIntValue() == 1) {
SDValue XORNode;
if (VT == VT0)
return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT0,
N0, DAG.getConstant(1, VT0));
XORNode = DAG.getNode(ISD::XOR, N0.getDebugLoc(), VT0,
N0, DAG.getConstant(1, VT0));
AddToWorkList(XORNode.getNode());
if (VT.bitsGT(VT0))
return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, XORNode);
return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, XORNode);
}
// fold (select C, 0, X) -> (and (not C), X)
if (VT == VT0 && VT == MVT::i1 && N1C && N1C->isNullValue()) {
SDValue NOTNode = DAG.getNOT(N0.getDebugLoc(), N0, VT);
AddToWorkList(NOTNode.getNode());
return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, NOTNode, N2);
}
// fold (select C, X, 1) -> (or (not C), X)
if (VT == VT0 && VT == MVT::i1 && N2C && N2C->getAPIntValue() == 1) {
SDValue NOTNode = DAG.getNOT(N0.getDebugLoc(), N0, VT);
AddToWorkList(NOTNode.getNode());
return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, NOTNode, N1);
}
// fold (select C, X, 0) -> (and C, X)
if (VT == MVT::i1 && N2C && N2C->isNullValue())
return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, N1);
// fold (select X, X, Y) -> (or X, Y)
// fold (select X, 1, Y) -> (or X, Y)
if (VT == MVT::i1 && (N0 == N1 || (N1C && N1C->getAPIntValue() == 1)))
return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, N0, N2);
// fold (select X, Y, X) -> (and X, Y)
// fold (select X, Y, 0) -> (and X, Y)
if (VT == MVT::i1 && (N0 == N2 || (N2C && N2C->getAPIntValue() == 0)))
return DAG.getNode(ISD::AND, N->getDebugLoc(), VT, N0, N1);
// If we can fold this based on the true/false value, do so.
if (SimplifySelectOps(N, N1, N2))
return SDValue(N, 0); // Don't revisit N.
// fold selects based on a setcc into other things, such as min/max/abs
if (N0.getOpcode() == ISD::SETCC) {
// FIXME:
// Check against MVT::Other for SELECT_CC, which is a workaround for targets
// having to say they don't support SELECT_CC on every type the DAG knows
// about, since there is no way to mark an opcode illegal at all value types
if (TLI.isOperationLegalOrCustom(ISD::SELECT_CC, MVT::Other) &&
TLI.isOperationLegalOrCustom(ISD::SELECT_CC, VT))
return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), VT,
N0.getOperand(0), N0.getOperand(1),
N1, N2, N0.getOperand(2));
return SimplifySelect(N->getDebugLoc(), N0, N1, N2);
}
return SDValue();
}
SDValue DAGCombiner::visitSELECT_CC(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
SDValue N2 = N->getOperand(2);
SDValue N3 = N->getOperand(3);
SDValue N4 = N->getOperand(4);
ISD::CondCode CC = cast<CondCodeSDNode>(N4)->get();
// fold select_cc lhs, rhs, x, x, cc -> x
if (N2 == N3)
return N2;
// Determine if the condition we're dealing with is constant
SDValue SCC = SimplifySetCC(TLI.getSetCCResultType(N0.getValueType()),
N0, N1, CC, N->getDebugLoc(), false);
if (SCC.getNode()) AddToWorkList(SCC.getNode());
if (ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.getNode())) {
if (!SCCC->isNullValue())
return N2; // cond always true -> true val
else
return N3; // cond always false -> false val
}
// Fold to a simpler select_cc
if (SCC.getNode() && SCC.getOpcode() == ISD::SETCC)
return DAG.getNode(ISD::SELECT_CC, N->getDebugLoc(), N2.getValueType(),
SCC.getOperand(0), SCC.getOperand(1), N2, N3,
SCC.getOperand(2));
// If we can fold this based on the true/false value, do so.
if (SimplifySelectOps(N, N2, N3))
return SDValue(N, 0); // Don't revisit N.
// fold select_cc into other things, such as min/max/abs
return SimplifySelectCC(N->getDebugLoc(), N0, N1, N2, N3, CC);
}
SDValue DAGCombiner::visitSETCC(SDNode *N) {
return SimplifySetCC(N->getValueType(0), N->getOperand(0), N->getOperand(1),
cast<CondCodeSDNode>(N->getOperand(2))->get(),
N->getDebugLoc());
}
// ExtendUsesToFormExtLoad - Trying to extend uses of a load to enable this:
// "fold ({s|z|a}ext (load x)) -> ({s|z|a}ext (truncate ({s|z|a}extload x)))"
// transformation. Returns true if extension are possible and the above
// mentioned transformation is profitable.
static bool ExtendUsesToFormExtLoad(SDNode *N, SDValue N0,
unsigned ExtOpc,
SmallVector<SDNode*, 4> &ExtendNodes,
const TargetLowering &TLI) {
bool HasCopyToRegUses = false;
bool isTruncFree = TLI.isTruncateFree(N->getValueType(0), N0.getValueType());
for (SDNode::use_iterator UI = N0.getNode()->use_begin(),
UE = N0.getNode()->use_end();
UI != UE; ++UI) {
SDNode *User = *UI;
if (User == N)
continue;
if (UI.getUse().getResNo() != N0.getResNo())
continue;
// FIXME: Only extend SETCC N, N and SETCC N, c for now.
if (ExtOpc != ISD::ANY_EXTEND && User->getOpcode() == ISD::SETCC) {
ISD::CondCode CC = cast<CondCodeSDNode>(User->getOperand(2))->get();
if (ExtOpc == ISD::ZERO_EXTEND && ISD::isSignedIntSetCC(CC))
// Sign bits will be lost after a zext.
return false;
bool Add = false;
for (unsigned i = 0; i != 2; ++i) {
SDValue UseOp = User->getOperand(i);
if (UseOp == N0)
continue;
if (!isa<ConstantSDNode>(UseOp))
return false;
Add = true;
}
if (Add)
ExtendNodes.push_back(User);
continue;
}
// If truncates aren't free and there are users we can't
// extend, it isn't worthwhile.
if (!isTruncFree)
return false;
// Remember if this value is live-out.
if (User->getOpcode() == ISD::CopyToReg)
HasCopyToRegUses = true;
}
if (HasCopyToRegUses) {
bool BothLiveOut = false;
for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end();
UI != UE; ++UI) {
SDUse &Use = UI.getUse();
if (Use.getResNo() == 0 && Use.getUser()->getOpcode() == ISD::CopyToReg) {
BothLiveOut = true;
break;
}
}
if (BothLiveOut)
// Both unextended and extended values are live out. There had better be
// a good reason for the transformation.
return ExtendNodes.size();
}
return true;
}
void DAGCombiner::ExtendSetCCUses(SmallVector<SDNode*, 4> SetCCs,
SDValue Trunc, SDValue ExtLoad, DebugLoc DL,
ISD::NodeType ExtType) {
// Extend SetCC uses if necessary.
for (unsigned i = 0, e = SetCCs.size(); i != e; ++i) {
SDNode *SetCC = SetCCs[i];
SmallVector<SDValue, 4> Ops;
for (unsigned j = 0; j != 2; ++j) {
SDValue SOp = SetCC->getOperand(j);
if (SOp == Trunc)
Ops.push_back(ExtLoad);
else
Ops.push_back(DAG.getNode(ExtType, DL, ExtLoad->getValueType(0), SOp));
}
Ops.push_back(SetCC->getOperand(2));
CombineTo(SetCC, DAG.getNode(ISD::SETCC, DL, SetCC->getValueType(0),
&Ops[0], Ops.size()));
}
}
SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
// fold (sext c1) -> c1
if (isa<ConstantSDNode>(N0))
return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, N0);
// fold (sext (sext x)) -> (sext x)
// fold (sext (aext x)) -> (sext x)
if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND)
return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT,
N0.getOperand(0));
if (N0.getOpcode() == ISD::TRUNCATE) {
// fold (sext (truncate (load x))) -> (sext (smaller load x))
// fold (sext (truncate (srl (load x), c))) -> (sext (smaller load (x+c/n)))
SDValue NarrowLoad = ReduceLoadWidth(N0.getNode());
if (NarrowLoad.getNode()) {
SDNode* oye = N0.getNode()->getOperand(0).getNode();
if (NarrowLoad.getNode() != N0.getNode()) {
CombineTo(N0.getNode(), NarrowLoad);
// CombineTo deleted the truncate, if needed, but not what's under it.
AddToWorkList(oye);
}
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
// See if the value being truncated is already sign extended. If so, just
// eliminate the trunc/sext pair.
SDValue Op = N0.getOperand(0);
unsigned OpBits = Op.getValueType().getScalarType().getSizeInBits();
unsigned MidBits = N0.getValueType().getScalarType().getSizeInBits();
unsigned DestBits = VT.getScalarType().getSizeInBits();
unsigned NumSignBits = DAG.ComputeNumSignBits(Op);
if (OpBits == DestBits) {
// Op is i32, Mid is i8, and Dest is i32. If Op has more than 24 sign
// bits, it is already ready.
if (NumSignBits > DestBits-MidBits)
return Op;
} else if (OpBits < DestBits) {
// Op is i32, Mid is i8, and Dest is i64. If Op has more than 24 sign
// bits, just sext from i32.
if (NumSignBits > OpBits-MidBits)
return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, Op);
} else {
// Op is i64, Mid is i8, and Dest is i32. If Op has more than 56 sign
// bits, just truncate to i32.
if (NumSignBits > OpBits-MidBits)
return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Op);
}
// fold (sext (truncate x)) -> (sextinreg x).
if (!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG,
N0.getValueType())) {
if (OpBits < DestBits)
Op = DAG.getNode(ISD::ANY_EXTEND, N0.getDebugLoc(), VT, Op);
else if (OpBits > DestBits)
Op = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), VT, Op);
return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT, Op,
DAG.getValueType(N0.getValueType()));
}
}
// fold (sext (load x)) -> (sext (truncate (sextload x)))
// None of the supported targets knows how to perform load and sign extend
// on vectors in one instruction. We only perform this transformation on
// scalars.
if (ISD::isNON_EXTLoad(N0.getNode()) && !VT.isVector() &&
((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
TLI.isLoadExtLegal(ISD::SEXTLOAD, N0.getValueType()))) {
bool DoXform = true;
SmallVector<SDNode*, 4> SetCCs;
if (!N0.hasOneUse())
DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::SIGN_EXTEND, SetCCs, TLI);
if (DoXform) {
LoadSDNode *LN0 = cast<LoadSDNode>(N0);
SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, N->getDebugLoc(), VT,
LN0->getChain(),
LN0->getBasePtr(), LN0->getPointerInfo(),
N0.getValueType(),
LN0->isVolatile(), LN0->isNonTemporal(),
LN0->getAlignment());
CombineTo(N, ExtLoad);
SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(),
N0.getValueType(), ExtLoad);
CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1));
ExtendSetCCUses(SetCCs, Trunc, ExtLoad, N->getDebugLoc(),
ISD::SIGN_EXTEND);
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
}
// fold (sext (sextload x)) -> (sext (truncate (sextload x)))
// fold (sext ( extload x)) -> (sext (truncate (sextload x)))
if ((ISD::isSEXTLoad(N0.getNode()) || ISD::isEXTLoad(N0.getNode())) &&
ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) {
LoadSDNode *LN0 = cast<LoadSDNode>(N0);
EVT MemVT = LN0->getMemoryVT();
if ((!LegalOperations && !LN0->isVolatile()) ||
TLI.isLoadExtLegal(ISD::SEXTLOAD, MemVT)) {
SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, N->getDebugLoc(), VT,
LN0->getChain(),
LN0->getBasePtr(), LN0->getPointerInfo(),
MemVT,
LN0->isVolatile(), LN0->isNonTemporal(),
LN0->getAlignment());
CombineTo(N, ExtLoad);
CombineTo(N0.getNode(),
DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(),
N0.getValueType(), ExtLoad),
ExtLoad.getValue(1));
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
}
// fold (sext (and/or/xor (load x), cst)) ->
// (and/or/xor (sextload x), (sext cst))
if ((N0.getOpcode() == ISD::AND || N0.getOpcode() == ISD::OR ||
N0.getOpcode() == ISD::XOR) &&
isa<LoadSDNode>(N0.getOperand(0)) &&
N0.getOperand(1).getOpcode() == ISD::Constant &&
TLI.isLoadExtLegal(ISD::SEXTLOAD, N0.getValueType()) &&
(!LegalOperations && TLI.isOperationLegal(N0.getOpcode(), VT))) {
LoadSDNode *LN0 = cast<LoadSDNode>(N0.getOperand(0));
if (LN0->getExtensionType() != ISD::ZEXTLOAD) {
bool DoXform = true;
SmallVector<SDNode*, 4> SetCCs;
if (!N0.hasOneUse())
DoXform = ExtendUsesToFormExtLoad(N, N0.getOperand(0), ISD::SIGN_EXTEND,
SetCCs, TLI);
if (DoXform) {
SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, LN0->getDebugLoc(), VT,
LN0->getChain(), LN0->getBasePtr(),
LN0->getPointerInfo(),
LN0->getMemoryVT(),
LN0->isVolatile(),
LN0->isNonTemporal(),
LN0->getAlignment());
APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
Mask = Mask.sext(VT.getSizeInBits());
SDValue And = DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT,
ExtLoad, DAG.getConstant(Mask, VT));
SDValue Trunc = DAG.getNode(ISD::TRUNCATE,
N0.getOperand(0).getDebugLoc(),
N0.getOperand(0).getValueType(), ExtLoad);
CombineTo(N, And);
CombineTo(N0.getOperand(0).getNode(), Trunc, ExtLoad.getValue(1));
ExtendSetCCUses(SetCCs, Trunc, ExtLoad, N->getDebugLoc(),
ISD::SIGN_EXTEND);
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
}
}
if (N0.getOpcode() == ISD::SETCC) {
// sext(setcc) -> sext_in_reg(vsetcc) for vectors.
// Only do this before legalize for now.
if (VT.isVector() && !LegalOperations) {
EVT N0VT = N0.getOperand(0).getValueType();
// We know that the # elements of the results is the same as the
// # elements of the compare (and the # elements of the compare result
// for that matter). Check to see that they are the same size. If so,
// we know that the element size of the sext'd result matches the
// element size of the compare operands.
if (VT.getSizeInBits() == N0VT.getSizeInBits())
return DAG.getSetCC(N->getDebugLoc(), VT, N0.getOperand(0),
N0.getOperand(1),
cast<CondCodeSDNode>(N0.getOperand(2))->get());
// If the desired elements are smaller or larger than the source
// elements we can use a matching integer vector type and then
// truncate/sign extend
else {
EVT MatchingElementType =
EVT::getIntegerVT(*DAG.getContext(),
N0VT.getScalarType().getSizeInBits());
EVT MatchingVectorType =
EVT::getVectorVT(*DAG.getContext(), MatchingElementType,
N0VT.getVectorNumElements());
SDValue VsetCC =
DAG.getSetCC(N->getDebugLoc(), MatchingVectorType, N0.getOperand(0),
N0.getOperand(1),
cast<CondCodeSDNode>(N0.getOperand(2))->get());
return DAG.getSExtOrTrunc(VsetCC, N->getDebugLoc(), VT);
}
}
// sext(setcc x, y, cc) -> (select_cc x, y, -1, 0, cc)
unsigned ElementWidth = VT.getScalarType().getSizeInBits();
SDValue NegOne =
DAG.getConstant(APInt::getAllOnesValue(ElementWidth), VT);
SDValue SCC =
SimplifySelectCC(N->getDebugLoc(), N0.getOperand(0), N0.getOperand(1),
NegOne, DAG.getConstant(0, VT),
cast<CondCodeSDNode>(N0.getOperand(2))->get(), true);
if (SCC.getNode()) return SCC;
if (!LegalOperations ||
TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultType(VT)))
return DAG.getNode(ISD::SELECT, N->getDebugLoc(), VT,
DAG.getSetCC(N->getDebugLoc(),
TLI.getSetCCResultType(VT),
N0.getOperand(0), N0.getOperand(1),
cast<CondCodeSDNode>(N0.getOperand(2))->get()),
NegOne, DAG.getConstant(0, VT));
}
// fold (sext x) -> (zext x) if the sign bit is known zero.
if ((!LegalOperations || TLI.isOperationLegal(ISD::ZERO_EXTEND, VT)) &&
DAG.SignBitIsZero(N0))
return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, N0);
return SDValue();
}
SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) {
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
// fold (zext c1) -> c1
if (isa<ConstantSDNode>(N0))
return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT, N0);
// fold (zext (zext x)) -> (zext x)
// fold (zext (aext x)) -> (zext x)
if (N0.getOpcode() == ISD::ZERO_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND)
return DAG.getNode(ISD::ZERO_EXTEND, N->getDebugLoc(), VT,
N0.getOperand(0));
// fold (zext (truncate (load x))) -> (zext (smaller load x))
// fold (zext (truncate (srl (load x), c))) -> (zext (small load (x+c/n)))
if (N0.getOpcode() == ISD::TRUNCATE) {
SDValue NarrowLoad = ReduceLoadWidth(N0.getNode());
if (NarrowLoad.getNode()) {
SDNode* oye = N0.getNode()->getOperand(0).getNode();
if (NarrowLoad.getNode() != N0.getNode()) {
CombineTo(N0.getNode(), NarrowLoad);
// CombineTo deleted the truncate, if needed, but not what's under it.
AddToWorkList(oye);
}
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
}
// fold (zext (truncate x)) -> (and x, mask)
if (N0.getOpcode() == ISD::TRUNCATE &&
(!LegalOperations || TLI.isOperationLegal(ISD::AND, VT))) {
// fold (zext (truncate (load x))) -> (zext (smaller load x))
// fold (zext (truncate (srl (load x), c))) -> (zext (smaller load (x+c/n)))
SDValue NarrowLoad = ReduceLoadWidth(N0.getNode());
if (NarrowLoad.getNode()) {
SDNode* oye = N0.getNode()->getOperand(0).getNode();
if (NarrowLoad.getNode() != N0.getNode()) {
CombineTo(N0.getNode(), NarrowLoad);
// CombineTo deleted the truncate, if needed, but not what's under it.
AddToWorkList(oye);
}
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
SDValue Op = N0.getOperand(0);
if (Op.getValueType().bitsLT(VT)) {
Op = DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, Op);
} else if (Op.getValueType().bitsGT(VT)) {
Op = DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Op);
}
return DAG.getZeroExtendInReg(Op, N->getDebugLoc(),
N0.getValueType().getScalarType());
}
// Fold (zext (and (trunc x), cst)) -> (and x, cst),
// if either of the casts is not free.
if (N0.getOpcode() == ISD::AND &&
N0.getOperand(0).getOpcode() == ISD::TRUNCATE &&
N0.getOperand(1).getOpcode() == ISD::Constant &&
(!TLI.isTruncateFree(N0.getOperand(0).getOperand(0).getValueType(),
N0.getValueType()) ||
!TLI.isZExtFree(N0.getValueType(), VT))) {
SDValue X = N0.getOperand(0).getOperand(0);
if (X.getValueType().bitsLT(VT)) {
X = DAG.getNode(ISD::ANY_EXTEND, X.getDebugLoc(), VT, X);
} else if (X.getValueType().bitsGT(VT)) {
X = DAG.getNode(ISD::TRUNCATE, X.getDebugLoc(), VT, X);
}
APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
Mask = Mask.zext(VT.getSizeInBits());
return DAG.getNode(ISD::AND, N->getDebugLoc(), VT,
X, DAG.getConstant(Mask, VT));
}
// fold (zext (load x)) -> (zext (truncate (zextload x)))
// None of the supported targets knows how to perform load and vector_zext
// on vectors in one instruction. We only perform this transformation on
// scalars.
if (ISD::isNON_EXTLoad(N0.getNode()) && !VT.isVector() &&
((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
TLI.isLoadExtLegal(ISD::ZEXTLOAD, N0.getValueType()))) {
bool DoXform = true;
SmallVector<SDNode*, 4> SetCCs;
if (!N0.hasOneUse())
DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::ZERO_EXTEND, SetCCs, TLI);
if (DoXform) {
LoadSDNode *LN0 = cast<LoadSDNode>(N0);
SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, N->getDebugLoc(), VT,
LN0->getChain(),
LN0->getBasePtr(), LN0->getPointerInfo(),
N0.getValueType(),
LN0->isVolatile(), LN0->isNonTemporal(),
LN0->getAlignment());
CombineTo(N, ExtLoad);
SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(),
N0.getValueType(), ExtLoad);
CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1));
ExtendSetCCUses(SetCCs, Trunc, ExtLoad, N->getDebugLoc(),
ISD::ZERO_EXTEND);
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
}
// fold (zext (and/or/xor (load x), cst)) ->
// (and/or/xor (zextload x), (zext cst))
if ((N0.getOpcode() == ISD::AND || N0.getOpcode() == ISD::OR ||
N0.getOpcode() == ISD::XOR) &&
isa<LoadSDNode>(N0.getOperand(0)) &&
N0.getOperand(1).getOpcode() == ISD::Constant &&
TLI.isLoadExtLegal(ISD::ZEXTLOAD, N0.getValueType()) &&
(!LegalOperations && TLI.isOperationLegal(N0.getOpcode(), VT))) {
LoadSDNode *LN0 = cast<LoadSDNode>(N0.getOperand(0));
if (LN0->getExtensionType() != ISD::SEXTLOAD) {
bool DoXform = true;
SmallVector<SDNode*, 4> SetCCs;
if (!N0.hasOneUse())
DoXform = ExtendUsesToFormExtLoad(N, N0.getOperand(0), ISD::ZERO_EXTEND,
SetCCs, TLI);
if (DoXform) {
SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, LN0->getDebugLoc(), VT,
LN0->getChain(), LN0->getBasePtr(),
LN0->getPointerInfo(),
LN0->getMemoryVT(),
LN0->isVolatile(),
LN0->isNonTemporal(),
LN0->getAlignment());
APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
Mask = Mask.zext(VT.getSizeInBits());
SDValue And = DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT,
ExtLoad, DAG.getConstant(Mask, VT));
SDValue Trunc = DAG.getNode(ISD::TRUNCATE,
N0.getOperand(0).getDebugLoc(),
N0.getOperand(0).getValueType(), ExtLoad);
CombineTo(N, And);
CombineTo(N0.getOperand(0).getNode(), Trunc, ExtLoad.getValue(1));
ExtendSetCCUses(SetCCs, Trunc, ExtLoad, N->getDebugLoc(),
ISD::ZERO_EXTEND);
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
}
}
// fold (zext (zextload x)) -> (zext (truncate (zextload x)))
// fold (zext ( extload x)) -> (zext (truncate (zextload x)))
if ((ISD::isZEXTLoad(N0.getNode()) || ISD::isEXTLoad(N0.getNode())) &&
ISD::isUNINDEXEDLoad(N0.getNode()) && N0.hasOneUse()) {
LoadSDNode *LN0 = cast<LoadSDNode>(N0);
EVT MemVT = LN0->getMemoryVT();
if ((!LegalOperations && !LN0->isVolatile()) ||
TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT)) {
SDValue ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, N->getDebugLoc(), VT,
LN0->getChain(),
LN0->getBasePtr(), LN0->getPointerInfo(),
MemVT,
LN0->isVolatile(), LN0->isNonTemporal(),
LN0->getAlignment());
CombineTo(N, ExtLoad);
CombineTo(N0.getNode(),
DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), N0.getValueType(),
ExtLoad),
ExtLoad.getValue(1));
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
}
if (N0.getOpcode() == ISD::SETCC) {
if (!LegalOperations && VT.isVector()) {
// zext(setcc) -> (and (vsetcc), (1, 1, ...) for vectors.
// Only do this before legalize for now.
EVT N0VT = N0.getOperand(0).getValueType();
EVT EltVT = VT.getVectorElementType();
SmallVector<SDValue,8> OneOps(VT.getVectorNumElements(),
DAG.getConstant(1, EltVT));
if (VT.getSizeInBits() == N0VT.getSizeInBits())
// We know that the # elements of the results is the same as the
// # elements of the compare (and the # elements of the compare result
// for that matter). Check to see that they are the same size. If so,
// we know that the element size of the sext'd result matches the
// element size of the compare operands.
return DAG.getNode(ISD::AND, N->getDebugLoc(), VT,
DAG.getSetCC(N->getDebugLoc(), VT, N0.getOperand(0),
N0.getOperand(1),
cast<CondCodeSDNode>(N0.getOperand(2))->get()),
DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), VT,
&OneOps[0], OneOps.size()));
// If the desired elements are smaller or larger than the source
// elements we can use a matching integer vector type and then
// truncate/sign extend
EVT MatchingElementType =
EVT::getIntegerVT(*DAG.getContext(),
N0VT.getScalarType().getSizeInBits());
EVT MatchingVectorType =
EVT::getVectorVT(*DAG.getContext(), MatchingElementType,
N0VT.getVectorNumElements());
SDValue VsetCC =
DAG.getSetCC(N->getDebugLoc(), MatchingVectorType, N0.getOperand(0),
N0.getOperand(1),
cast<CondCodeSDNode>(N0.getOperand(2))->get());
return DAG.getNode(ISD::AND, N->getDebugLoc(), VT,
DAG.getSExtOrTrunc(VsetCC, N->getDebugLoc(), VT),
DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), VT,
&OneOps[0], OneOps.size()));
}
// zext(setcc x,y,cc) -> select_cc x, y, 1, 0, cc
SDValue SCC =
SimplifySelectCC(N->getDebugLoc(), N0.getOperand(0), N0.getOperand(1),
DAG.getConstant(1, VT), DAG.getConstant(0, VT),
cast<CondCodeSDNode>(N0.getOperand(2))->get(), true);
if (SCC.getNode()) return SCC;
}
// (zext (shl (zext x), cst)) -> (shl (zext x), cst)
if ((N0.getOpcode() == ISD::SHL || N0.getOpcode() == ISD::SRL) &&
isa<ConstantSDNode>(N0.getOperand(1)) &&
N0.getOperand(0).getOpcode() == ISD::ZERO_EXTEND &&
N0.hasOneUse()) {
SDValue ShAmt = N0.getOperand(1);
unsigned ShAmtVal = cast<ConstantSDNode>(ShAmt)->getZExtValue();
if (N0.getOpcode() == ISD::SHL) {
SDValue InnerZExt = N0.getOperand(0);
// If the original shl may be shifting out bits, do not perform this
// transformation.
unsigned KnownZeroBits = InnerZExt.getValueType().getSizeInBits() -
InnerZExt.getOperand(0).getValueType().getSizeInBits();
if (ShAmtVal > KnownZeroBits)
return SDValue();
}
DebugLoc DL = N->getDebugLoc();
// Ensure that the shift amount is wide enough for the shifted value.
if (VT.getSizeInBits() >= 256)
ShAmt = DAG.getNode(ISD::ZERO_EXTEND, DL, MVT::i32, ShAmt);
return DAG.getNode(N0.getOpcode(), DL, VT,
DAG.getNode(ISD::ZERO_EXTEND, DL, VT, N0.getOperand(0)),
ShAmt);
}
return SDValue();
}
SDValue DAGCombiner::visitANY_EXTEND(SDNode *N) {
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
// fold (aext c1) -> c1
if (isa<ConstantSDNode>(N0))
return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, N0);
// fold (aext (aext x)) -> (aext x)
// fold (aext (zext x)) -> (zext x)
// fold (aext (sext x)) -> (sext x)
if (N0.getOpcode() == ISD::ANY_EXTEND ||
N0.getOpcode() == ISD::ZERO_EXTEND ||
N0.getOpcode() == ISD::SIGN_EXTEND)
return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, N0.getOperand(0));
// fold (aext (truncate (load x))) -> (aext (smaller load x))
// fold (aext (truncate (srl (load x), c))) -> (aext (small load (x+c/n)))
if (N0.getOpcode() == ISD::TRUNCATE) {
SDValue NarrowLoad = ReduceLoadWidth(N0.getNode());
if (NarrowLoad.getNode()) {
SDNode* oye = N0.getNode()->getOperand(0).getNode();
if (NarrowLoad.getNode() != N0.getNode()) {
CombineTo(N0.getNode(), NarrowLoad);
// CombineTo deleted the truncate, if needed, but not what's under it.
AddToWorkList(oye);
}
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
}
// fold (aext (truncate x))
if (N0.getOpcode() == ISD::TRUNCATE) {
SDValue TruncOp = N0.getOperand(0);
if (TruncOp.getValueType() == VT)
return TruncOp; // x iff x size == zext size.
if (TruncOp.getValueType().bitsGT(VT))
return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, TruncOp);
return DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, TruncOp);
}
// Fold (aext (and (trunc x), cst)) -> (and x, cst)
// if the trunc is not free.
if (N0.getOpcode() == ISD::AND &&
N0.getOperand(0).getOpcode() == ISD::TRUNCATE &&
N0.getOperand(1).getOpcode() == ISD::Constant &&
!TLI.isTruncateFree(N0.getOperand(0).getOperand(0).getValueType(),
N0.getValueType())) {
SDValue X = N0.getOperand(0).getOperand(0);
if (X.getValueType().bitsLT(VT)) {
X = DAG.getNode(ISD::ANY_EXTEND, N->getDebugLoc(), VT, X);
} else if (X.getValueType().bitsGT(VT)) {
X = DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, X);
}
APInt Mask = cast<ConstantSDNode>(N0.getOperand(1))->getAPIntValue();
Mask = Mask.zext(VT.getSizeInBits());
return DAG.getNode(ISD::AND, N->getDebugLoc(), VT,
X, DAG.getConstant(Mask, VT));
}
// fold (aext (load x)) -> (aext (truncate (extload x)))
// None of the supported targets knows how to perform load and any_ext
// on vectors in one instruction. We only perform this transformation on
// scalars.
if (ISD::isNON_EXTLoad(N0.getNode()) && !VT.isVector() &&
((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
TLI.isLoadExtLegal(ISD::EXTLOAD, N0.getValueType()))) {
bool DoXform = true;
SmallVector<SDNode*, 4> SetCCs;
if (!N0.hasOneUse())
DoXform = ExtendUsesToFormExtLoad(N, N0, ISD::ANY_EXTEND, SetCCs, TLI);
if (DoXform) {
LoadSDNode *LN0 = cast<LoadSDNode>(N0);
SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, N->getDebugLoc(), VT,
LN0->getChain(),
LN0->getBasePtr(), LN0->getPointerInfo(),
N0.getValueType(),
LN0->isVolatile(), LN0->isNonTemporal(),
LN0->getAlignment());
CombineTo(N, ExtLoad);
SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(),
N0.getValueType(), ExtLoad);
CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1));
ExtendSetCCUses(SetCCs, Trunc, ExtLoad, N->getDebugLoc(),
ISD::ANY_EXTEND);
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
}
// fold (aext (zextload x)) -> (aext (truncate (zextload x)))
// fold (aext (sextload x)) -> (aext (truncate (sextload x)))
// fold (aext ( extload x)) -> (aext (truncate (extload x)))
if (N0.getOpcode() == ISD::LOAD &&
!ISD::isNON_EXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) &&
N0.hasOneUse()) {
LoadSDNode *LN0 = cast<LoadSDNode>(N0);
EVT MemVT = LN0->getMemoryVT();
SDValue ExtLoad = DAG.getExtLoad(LN0->getExtensionType(), N->getDebugLoc(),
VT, LN0->getChain(), LN0->getBasePtr(),
LN0->getPointerInfo(), MemVT,
LN0->isVolatile(), LN0->isNonTemporal(),
LN0->getAlignment());
CombineTo(N, ExtLoad);
CombineTo(N0.getNode(),
DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(),
N0.getValueType(), ExtLoad),
ExtLoad.getValue(1));
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
if (N0.getOpcode() == ISD::SETCC) {
// aext(setcc) -> sext_in_reg(vsetcc) for vectors.
// Only do this before legalize for now.
if (VT.isVector() && !LegalOperations) {
EVT N0VT = N0.getOperand(0).getValueType();
// We know that the # elements of the results is the same as the
// # elements of the compare (and the # elements of the compare result
// for that matter). Check to see that they are the same size. If so,
// we know that the element size of the sext'd result matches the
// element size of the compare operands.
if (VT.getSizeInBits() == N0VT.getSizeInBits())
return DAG.getSetCC(N->getDebugLoc(), VT, N0.getOperand(0),
N0.getOperand(1),
cast<CondCodeSDNode>(N0.getOperand(2))->get());
// If the desired elements are smaller or larger than the source
// elements we can use a matching integer vector type and then
// truncate/sign extend
else {
EVT MatchingElementType =
EVT::getIntegerVT(*DAG.getContext(),
N0VT.getScalarType().getSizeInBits());
EVT MatchingVectorType =
EVT::getVectorVT(*DAG.getContext(), MatchingElementType,
N0VT.getVectorNumElements());
SDValue VsetCC =
DAG.getSetCC(N->getDebugLoc(), MatchingVectorType, N0.getOperand(0),
N0.getOperand(1),
cast<CondCodeSDNode>(N0.getOperand(2))->get());
return DAG.getSExtOrTrunc(VsetCC, N->getDebugLoc(), VT);
}
}
// aext(setcc x,y,cc) -> select_cc x, y, 1, 0, cc
SDValue SCC =
SimplifySelectCC(N->getDebugLoc(), N0.getOperand(0), N0.getOperand(1),
DAG.getConstant(1, VT), DAG.getConstant(0, VT),
cast<CondCodeSDNode>(N0.getOperand(2))->get(), true);
if (SCC.getNode())
return SCC;
}
return SDValue();
}
/// GetDemandedBits - See if the specified operand can be simplified with the
/// knowledge that only the bits specified by Mask are used. If so, return the
/// simpler operand, otherwise return a null SDValue.
SDValue DAGCombiner::GetDemandedBits(SDValue V, const APInt &Mask) {
switch (V.getOpcode()) {
default: break;
case ISD::OR:
case ISD::XOR:
// If the LHS or RHS don't contribute bits to the or, drop them.
if (DAG.MaskedValueIsZero(V.getOperand(0), Mask))
return V.getOperand(1);
if (DAG.MaskedValueIsZero(V.getOperand(1), Mask))
return V.getOperand(0);
break;
case ISD::SRL:
// Only look at single-use SRLs.
if (!V.getNode()->hasOneUse())
break;
if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(V.getOperand(1))) {
// See if we can recursively simplify the LHS.
unsigned Amt = RHSC->getZExtValue();
// Watch out for shift count overflow though.
if (Amt >= Mask.getBitWidth()) break;
APInt NewMask = Mask << Amt;
SDValue SimplifyLHS = GetDemandedBits(V.getOperand(0), NewMask);
if (SimplifyLHS.getNode())
return DAG.getNode(ISD::SRL, V.getDebugLoc(), V.getValueType(),
SimplifyLHS, V.getOperand(1));
}
}
return SDValue();
}
/// ReduceLoadWidth - If the result of a wider load is shifted to right of N
/// bits and then truncated to a narrower type and where N is a multiple
/// of number of bits of the narrower type, transform it to a narrower load
/// from address + N / num of bits of new type. If the result is to be
/// extended, also fold the extension to form a extending load.
SDValue DAGCombiner::ReduceLoadWidth(SDNode *N) {
unsigned Opc = N->getOpcode();
ISD::LoadExtType ExtType = ISD::NON_EXTLOAD;
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
EVT ExtVT = VT;
// This transformation isn't valid for vector loads.
if (VT.isVector())
return SDValue();
// Special case: SIGN_EXTEND_INREG is basically truncating to ExtVT then
// extended to VT.
if (Opc == ISD::SIGN_EXTEND_INREG) {
ExtType = ISD::SEXTLOAD;
ExtVT = cast<VTSDNode>(N->getOperand(1))->getVT();
} else if (Opc == ISD::SRL) {
// Another special-case: SRL is basically zero-extending a narrower value.
ExtType = ISD::ZEXTLOAD;
N0 = SDValue(N, 0);
ConstantSDNode *N01 = dyn_cast<ConstantSDNode>(N0.getOperand(1));
if (!N01) return SDValue();
ExtVT = EVT::getIntegerVT(*DAG.getContext(),
VT.getSizeInBits() - N01->getZExtValue());
}
if (LegalOperations && !TLI.isLoadExtLegal(ExtType, ExtVT))
return SDValue();
unsigned EVTBits = ExtVT.getSizeInBits();
// Do not generate loads of non-round integer types since these can
// be expensive (and would be wrong if the type is not byte sized).
if (!ExtVT.isRound())
return SDValue();
unsigned ShAmt = 0;
if (N0.getOpcode() == ISD::SRL && N0.hasOneUse()) {
if (ConstantSDNode *N01 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
ShAmt = N01->getZExtValue();
// Is the shift amount a multiple of size of VT?
if ((ShAmt & (EVTBits-1)) == 0) {
N0 = N0.getOperand(0);
// Is the load width a multiple of size of VT?
if ((N0.getValueType().getSizeInBits() & (EVTBits-1)) != 0)
return SDValue();
}
// At this point, we must have a load or else we can't do the transform.
if (!isa<LoadSDNode>(N0)) return SDValue();
// If the shift amount is larger than the input type then we're not
// accessing any of the loaded bytes. If the load was a zextload/extload
// then the result of the shift+trunc is zero/undef (handled elsewhere).
// If the load was a sextload then the result is a splat of the sign bit
// of the extended byte. This is not worth optimizing for.
if (ShAmt >= cast<LoadSDNode>(N0)->getMemoryVT().getSizeInBits())
return SDValue();
}
}
// If the load is shifted left (and the result isn't shifted back right),
// we can fold the truncate through the shift.
unsigned ShLeftAmt = 0;
if (ShAmt == 0 && N0.getOpcode() == ISD::SHL && N0.hasOneUse() &&
ExtVT == VT && TLI.isNarrowingProfitable(N0.getValueType(), VT)) {
if (ConstantSDNode *N01 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
ShLeftAmt = N01->getZExtValue();
N0 = N0.getOperand(0);
}
}
// If we haven't found a load, we can't narrow it. Don't transform one with
// multiple uses, this would require adding a new load.
if (!isa<LoadSDNode>(N0) || !N0.hasOneUse() ||
// Don't change the width of a volatile load.
cast<LoadSDNode>(N0)->isVolatile())
return SDValue();
// Verify that we are actually reducing a load width here.
if (cast<LoadSDNode>(N0)->getMemoryVT().getSizeInBits() < EVTBits)
return SDValue();
LoadSDNode *LN0 = cast<LoadSDNode>(N0);
EVT PtrType = N0.getOperand(1).getValueType();
// For big endian targets, we need to adjust the offset to the pointer to
// load the correct bytes.
if (TLI.isBigEndian()) {
unsigned LVTStoreBits = LN0->getMemoryVT().getStoreSizeInBits();
unsigned EVTStoreBits = ExtVT.getStoreSizeInBits();
ShAmt = LVTStoreBits - EVTStoreBits - ShAmt;
}
uint64_t PtrOff = ShAmt / 8;
unsigned NewAlign = MinAlign(LN0->getAlignment(), PtrOff);
SDValue NewPtr = DAG.getNode(ISD::ADD, LN0->getDebugLoc(),
PtrType, LN0->getBasePtr(),
DAG.getConstant(PtrOff, PtrType));
AddToWorkList(NewPtr.getNode());
SDValue Load;
if (ExtType == ISD::NON_EXTLOAD)
Load = DAG.getLoad(VT, N0.getDebugLoc(), LN0->getChain(), NewPtr,
LN0->getPointerInfo().getWithOffset(PtrOff),
LN0->isVolatile(), LN0->isNonTemporal(), NewAlign);
else
Load = DAG.getExtLoad(ExtType, N0.getDebugLoc(), VT, LN0->getChain(),NewPtr,
LN0->getPointerInfo().getWithOffset(PtrOff),
ExtVT, LN0->isVolatile(), LN0->isNonTemporal(),
NewAlign);
// Replace the old load's chain with the new load's chain.
WorkListRemover DeadNodes(*this);
DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), Load.getValue(1),
&DeadNodes);
// Shift the result left, if we've swallowed a left shift.
SDValue Result = Load;
if (ShLeftAmt != 0) {
EVT ShImmTy = getShiftAmountTy(Result.getValueType());
if (!isUIntN(ShImmTy.getSizeInBits(), ShLeftAmt))
ShImmTy = VT;
Result = DAG.getNode(ISD::SHL, N0.getDebugLoc(), VT,
Result, DAG.getConstant(ShLeftAmt, ShImmTy));
}
// Return the new loaded value.
return Result;
}
SDValue DAGCombiner::visitSIGN_EXTEND_INREG(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
EVT VT = N->getValueType(0);
EVT EVT = cast<VTSDNode>(N1)->getVT();
unsigned VTBits = VT.getScalarType().getSizeInBits();
unsigned EVTBits = EVT.getScalarType().getSizeInBits();
// fold (sext_in_reg c1) -> c1
if (isa<ConstantSDNode>(N0) || N0.getOpcode() == ISD::UNDEF)
return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT, N0, N1);
// If the input is already sign extended, just drop the extension.
if (DAG.ComputeNumSignBits(N0) >= VTBits-EVTBits+1)
return N0;
// fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt2
if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
EVT.bitsLT(cast<VTSDNode>(N0.getOperand(1))->getVT())) {
return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT,
N0.getOperand(0), N1);
}
// fold (sext_in_reg (sext x)) -> (sext x)
// fold (sext_in_reg (aext x)) -> (sext x)
// if x is small enough.
if (N0.getOpcode() == ISD::SIGN_EXTEND || N0.getOpcode() == ISD::ANY_EXTEND) {
SDValue N00 = N0.getOperand(0);
if (N00.getValueType().getScalarType().getSizeInBits() <= EVTBits &&
(!LegalOperations || TLI.isOperationLegal(ISD::SIGN_EXTEND, VT)))
return DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, N00, N1);
}
// fold (sext_in_reg x) -> (zext_in_reg x) if the sign bit is known zero.
if (DAG.MaskedValueIsZero(N0, APInt::getBitsSet(VTBits, EVTBits-1, EVTBits)))
return DAG.getZeroExtendInReg(N0, N->getDebugLoc(), EVT);
// fold operands of sext_in_reg based on knowledge that the top bits are not
// demanded.
if (SimplifyDemandedBits(SDValue(N, 0)))
return SDValue(N, 0);
// fold (sext_in_reg (load x)) -> (smaller sextload x)
// fold (sext_in_reg (srl (load x), c)) -> (smaller sextload (x+c/evtbits))
SDValue NarrowLoad = ReduceLoadWidth(N);
if (NarrowLoad.getNode())
return NarrowLoad;
// fold (sext_in_reg (srl X, 24), i8) -> (sra X, 24)
// fold (sext_in_reg (srl X, 23), i8) -> (sra X, 23) iff possible.
// We already fold "(sext_in_reg (srl X, 25), i8) -> srl X, 25" above.
if (N0.getOpcode() == ISD::SRL) {
if (ConstantSDNode *ShAmt = dyn_cast<ConstantSDNode>(N0.getOperand(1)))
if (ShAmt->getZExtValue()+EVTBits <= VTBits) {
// We can turn this into an SRA iff the input to the SRL is already sign
// extended enough.
unsigned InSignBits = DAG.ComputeNumSignBits(N0.getOperand(0));
if (VTBits-(ShAmt->getZExtValue()+EVTBits) < InSignBits)
return DAG.getNode(ISD::SRA, N->getDebugLoc(), VT,
N0.getOperand(0), N0.getOperand(1));
}
}
// fold (sext_inreg (extload x)) -> (sextload x)
if (ISD::isEXTLoad(N0.getNode()) &&
ISD::isUNINDEXEDLoad(N0.getNode()) &&
EVT == cast<LoadSDNode>(N0)->getMemoryVT() &&
((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT))) {
LoadSDNode *LN0 = cast<LoadSDNode>(N0);
SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, N->getDebugLoc(), VT,
LN0->getChain(),
LN0->getBasePtr(), LN0->getPointerInfo(),
EVT,
LN0->isVolatile(), LN0->isNonTemporal(),
LN0->getAlignment());
CombineTo(N, ExtLoad);
CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1));
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
// fold (sext_inreg (zextload x)) -> (sextload x) iff load has one use
if (ISD::isZEXTLoad(N0.getNode()) && ISD::isUNINDEXEDLoad(N0.getNode()) &&
N0.hasOneUse() &&
EVT == cast<LoadSDNode>(N0)->getMemoryVT() &&
((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
TLI.isLoadExtLegal(ISD::SEXTLOAD, EVT))) {
LoadSDNode *LN0 = cast<LoadSDNode>(N0);
SDValue ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, N->getDebugLoc(), VT,
LN0->getChain(),
LN0->getBasePtr(), LN0->getPointerInfo(),
EVT,
LN0->isVolatile(), LN0->isNonTemporal(),
LN0->getAlignment());
CombineTo(N, ExtLoad);
CombineTo(N0.getNode(), ExtLoad, ExtLoad.getValue(1));
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
// Form (sext_inreg (bswap >> 16)) or (sext_inreg (rotl (bswap) 16))
if (EVTBits <= 16 && N0.getOpcode() == ISD::OR) {
SDValue BSwap = MatchBSwapHWordLow(N0.getNode(), N0.getOperand(0),
N0.getOperand(1), false);
if (BSwap.getNode() != 0)
return DAG.getNode(ISD::SIGN_EXTEND_INREG, N->getDebugLoc(), VT,
BSwap, N1);
}
return SDValue();
}
SDValue DAGCombiner::visitTRUNCATE(SDNode *N) {
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
// noop truncate
if (N0.getValueType() == N->getValueType(0))
return N0;
// fold (truncate c1) -> c1
if (isa<ConstantSDNode>(N0))
return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, N0);
// fold (truncate (truncate x)) -> (truncate x)
if (N0.getOpcode() == ISD::TRUNCATE)
return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, N0.getOperand(0));
// fold (truncate (ext x)) -> (ext x) or (truncate x) or x
if (N0.getOpcode() == ISD::ZERO_EXTEND ||
N0.getOpcode() == ISD::SIGN_EXTEND ||
N0.getOpcode() == ISD::ANY_EXTEND) {
if (N0.getOperand(0).getValueType().bitsLT(VT))
// if the source is smaller than the dest, we still need an extend
return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT,
N0.getOperand(0));
else if (N0.getOperand(0).getValueType().bitsGT(VT))
// if the source is larger than the dest, than we just need the truncate
return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, N0.getOperand(0));
else
// if the source and dest are the same type, we can drop both the extend
// and the truncate.
return N0.getOperand(0);
}
// See if we can simplify the input to this truncate through knowledge that
// only the low bits are being used.
// For example "trunc (or (shl x, 8), y)" // -> trunc y
// Currently we only perform this optimization on scalars because vectors
// may have different active low bits.
if (!VT.isVector()) {
SDValue Shorter =
GetDemandedBits(N0, APInt::getLowBitsSet(N0.getValueSizeInBits(),
VT.getSizeInBits()));
if (Shorter.getNode())
return DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), VT, Shorter);
}
// fold (truncate (load x)) -> (smaller load x)
// fold (truncate (srl (load x), c)) -> (smaller load (x+c/evtbits))
if (!LegalTypes || TLI.isTypeDesirableForOp(N0.getOpcode(), VT)) {
SDValue Reduced = ReduceLoadWidth(N);
if (Reduced.getNode())
return Reduced;
}
// Simplify the operands using demanded-bits information.
if (!VT.isVector() &&
SimplifyDemandedBits(SDValue(N, 0)))
return SDValue(N, 0);
return SDValue();
}
static SDNode *getBuildPairElt(SDNode *N, unsigned i) {
SDValue Elt = N->getOperand(i);
if (Elt.getOpcode() != ISD::MERGE_VALUES)
return Elt.getNode();
return Elt.getOperand(Elt.getResNo()).getNode();
}
/// CombineConsecutiveLoads - build_pair (load, load) -> load
/// if load locations are consecutive.
SDValue DAGCombiner::CombineConsecutiveLoads(SDNode *N, EVT VT) {
assert(N->getOpcode() == ISD::BUILD_PAIR);
LoadSDNode *LD1 = dyn_cast<LoadSDNode>(getBuildPairElt(N, 0));
LoadSDNode *LD2 = dyn_cast<LoadSDNode>(getBuildPairElt(N, 1));
if (!LD1 || !LD2 || !ISD::isNON_EXTLoad(LD1) || !LD1->hasOneUse() ||
LD1->getPointerInfo().getAddrSpace() !=
LD2->getPointerInfo().getAddrSpace())
return SDValue();
EVT LD1VT = LD1->getValueType(0);
if (ISD::isNON_EXTLoad(LD2) &&
LD2->hasOneUse() &&
// If both are volatile this would reduce the number of volatile loads.
// If one is volatile it might be ok, but play conservative and bail out.
!LD1->isVolatile() &&
!LD2->isVolatile() &&
DAG.isConsecutiveLoad(LD2, LD1, LD1VT.getSizeInBits()/8, 1)) {
unsigned Align = LD1->getAlignment();
unsigned NewAlign = TLI.getTargetData()->
getABITypeAlignment(VT.getTypeForEVT(*DAG.getContext()));
if (NewAlign <= Align &&
(!LegalOperations || TLI.isOperationLegal(ISD::LOAD, VT)))
return DAG.getLoad(VT, N->getDebugLoc(), LD1->getChain(),
LD1->getBasePtr(), LD1->getPointerInfo(),
false, false, Align);
}
return SDValue();
}
SDValue DAGCombiner::visitBITCAST(SDNode *N) {
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
// If the input is a BUILD_VECTOR with all constant elements, fold this now.
// Only do this before legalize, since afterward the target may be depending
// on the bitconvert.
// First check to see if this is all constant.
if (!LegalTypes &&
N0.getOpcode() == ISD::BUILD_VECTOR && N0.getNode()->hasOneUse() &&
VT.isVector()) {
bool isSimple = true;
for (unsigned i = 0, e = N0.getNumOperands(); i != e; ++i)
if (N0.getOperand(i).getOpcode() != ISD::UNDEF &&
N0.getOperand(i).getOpcode() != ISD::Constant &&
N0.getOperand(i).getOpcode() != ISD::ConstantFP) {
isSimple = false;
break;
}
EVT DestEltVT = N->getValueType(0).getVectorElementType();
assert(!DestEltVT.isVector() &&
"Element type of vector ValueType must not be vector!");
if (isSimple)
return ConstantFoldBITCASTofBUILD_VECTOR(N0.getNode(), DestEltVT);
}
// If the input is a constant, let getNode fold it.
if (isa<ConstantSDNode>(N0) || isa<ConstantFPSDNode>(N0)) {
SDValue Res = DAG.getNode(ISD::BITCAST, N->getDebugLoc(), VT, N0);
if (Res.getNode() != N) {
if (!LegalOperations ||
TLI.isOperationLegal(Res.getNode()->getOpcode(), VT))
return Res;
// Folding it resulted in an illegal node, and it's too late to
// do that. Clean up the old node and forego the transformation.
// Ideally this won't happen very often, because instcombine
// and the earlier dagcombine runs (where illegal nodes are
// permitted) should have folded most of them already.
DAG.DeleteNode(Res.getNode());
}
}
// (conv (conv x, t1), t2) -> (conv x, t2)
if (N0.getOpcode() == ISD::BITCAST)
return DAG.getNode(ISD::BITCAST, N->getDebugLoc(), VT,
N0.getOperand(0));
// fold (conv (load x)) -> (load (conv*)x)
// If the resultant load doesn't need a higher alignment than the original!
if (ISD::isNormalLoad(N0.getNode()) && N0.hasOneUse() &&
// Do not change the width of a volatile load.
!cast<LoadSDNode>(N0)->isVolatile() &&
(!LegalOperations || TLI.isOperationLegal(ISD::LOAD, VT))) {
LoadSDNode *LN0 = cast<LoadSDNode>(N0);
unsigned Align = TLI.getTargetData()->
getABITypeAlignment(VT.getTypeForEVT(*DAG.getContext()));
unsigned OrigAlign = LN0->getAlignment();
if (Align <= OrigAlign) {
SDValue Load = DAG.getLoad(VT, N->getDebugLoc(), LN0->getChain(),
LN0->getBasePtr(), LN0->getPointerInfo(),
LN0->isVolatile(), LN0->isNonTemporal(),
OrigAlign);
AddToWorkList(N);
CombineTo(N0.getNode(),
DAG.getNode(ISD::BITCAST, N0.getDebugLoc(),
N0.getValueType(), Load),
Load.getValue(1));
return Load;
}
}
// fold (bitconvert (fneg x)) -> (xor (bitconvert x), signbit)
// fold (bitconvert (fabs x)) -> (and (bitconvert x), (not signbit))
// This often reduces constant pool loads.
if ((N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FABS) &&
N0.getNode()->hasOneUse() && VT.isInteger() && !VT.isVector()) {
SDValue NewConv = DAG.getNode(ISD::BITCAST, N0.getDebugLoc(), VT,
N0.getOperand(0));
AddToWorkList(NewConv.getNode());
APInt SignBit = APInt::getSignBit(VT.getSizeInBits());
if (N0.getOpcode() == ISD::FNEG)
return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT,
NewConv, DAG.getConstant(SignBit, VT));
assert(N0.getOpcode() == ISD::FABS);
return DAG.getNode(ISD::AND, N->getDebugLoc(), VT,
NewConv, DAG.getConstant(~SignBit, VT));
}
// fold (bitconvert (fcopysign cst, x)) ->
// (or (and (bitconvert x), sign), (and cst, (not sign)))
// Note that we don't handle (copysign x, cst) because this can always be
// folded to an fneg or fabs.
if (N0.getOpcode() == ISD::FCOPYSIGN && N0.getNode()->hasOneUse() &&
isa<ConstantFPSDNode>(N0.getOperand(0)) &&
VT.isInteger() && !VT.isVector()) {
unsigned OrigXWidth = N0.getOperand(1).getValueType().getSizeInBits();
EVT IntXVT = EVT::getIntegerVT(*DAG.getContext(), OrigXWidth);
if (isTypeLegal(IntXVT)) {
SDValue X = DAG.getNode(ISD::BITCAST, N0.getDebugLoc(),
IntXVT, N0.getOperand(1));
AddToWorkList(X.getNode());
// If X has a different width than the result/lhs, sext it or truncate it.
unsigned VTWidth = VT.getSizeInBits();
if (OrigXWidth < VTWidth) {
X = DAG.getNode(ISD::SIGN_EXTEND, N->getDebugLoc(), VT, X);
AddToWorkList(X.getNode());
} else if (OrigXWidth > VTWidth) {
// To get the sign bit in the right place, we have to shift it right
// before truncating.
X = DAG.getNode(ISD::SRL, X.getDebugLoc(),
X.getValueType(), X,
DAG.getConstant(OrigXWidth-VTWidth, X.getValueType()));
AddToWorkList(X.getNode());
X = DAG.getNode(ISD::TRUNCATE, X.getDebugLoc(), VT, X);
AddToWorkList(X.getNode());
}
APInt SignBit = APInt::getSignBit(VT.getSizeInBits());
X = DAG.getNode(ISD::AND, X.getDebugLoc(), VT,
X, DAG.getConstant(SignBit, VT));
AddToWorkList(X.getNode());
SDValue Cst = DAG.getNode(ISD::BITCAST, N0.getDebugLoc(),
VT, N0.getOperand(0));
Cst = DAG.getNode(ISD::AND, Cst.getDebugLoc(), VT,
Cst, DAG.getConstant(~SignBit, VT));
AddToWorkList(Cst.getNode());
return DAG.getNode(ISD::OR, N->getDebugLoc(), VT, X, Cst);
}
}
// bitconvert(build_pair(ld, ld)) -> ld iff load locations are consecutive.
if (N0.getOpcode() == ISD::BUILD_PAIR) {
SDValue CombineLD = CombineConsecutiveLoads(N0.getNode(), VT);
if (CombineLD.getNode())
return CombineLD;
}
return SDValue();
}
SDValue DAGCombiner::visitBUILD_PAIR(SDNode *N) {
EVT VT = N->getValueType(0);
return CombineConsecutiveLoads(N, VT);
}
/// ConstantFoldBITCASTofBUILD_VECTOR - We know that BV is a build_vector
/// node with Constant, ConstantFP or Undef operands. DstEltVT indicates the
/// destination element value type.
SDValue DAGCombiner::
ConstantFoldBITCASTofBUILD_VECTOR(SDNode *BV, EVT DstEltVT) {
EVT SrcEltVT = BV->getValueType(0).getVectorElementType();
// If this is already the right type, we're done.
if (SrcEltVT == DstEltVT) return SDValue(BV, 0);
unsigned SrcBitSize = SrcEltVT.getSizeInBits();
unsigned DstBitSize = DstEltVT.getSizeInBits();
// If this is a conversion of N elements of one type to N elements of another
// type, convert each element. This handles FP<->INT cases.
if (SrcBitSize == DstBitSize) {
EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT,
BV->getValueType(0).getVectorNumElements());
// Due to the FP element handling below calling this routine recursively,
// we can end up with a scalar-to-vector node here.
if (BV->getOpcode() == ISD::SCALAR_TO_VECTOR)
return DAG.getNode(ISD::SCALAR_TO_VECTOR, BV->getDebugLoc(), VT,
DAG.getNode(ISD::BITCAST, BV->getDebugLoc(),
DstEltVT, BV->getOperand(0)));
SmallVector<SDValue, 8> Ops;
for (unsigned i = 0, e = BV->getNumOperands(); i != e; ++i) {
SDValue Op = BV->getOperand(i);
// If the vector element type is not legal, the BUILD_VECTOR operands
// are promoted and implicitly truncated. Make that explicit here.
if (Op.getValueType() != SrcEltVT)
Op = DAG.getNode(ISD::TRUNCATE, BV->getDebugLoc(), SrcEltVT, Op);
Ops.push_back(DAG.getNode(ISD::BITCAST, BV->getDebugLoc(),
DstEltVT, Op));
AddToWorkList(Ops.back().getNode());
}
return DAG.getNode(ISD::BUILD_VECTOR, BV->getDebugLoc(), VT,
&Ops[0], Ops.size());
}
// Otherwise, we're growing or shrinking the elements. To avoid having to
// handle annoying details of growing/shrinking FP values, we convert them to
// int first.
if (SrcEltVT.isFloatingPoint()) {
// Convert the input float vector to a int vector where the elements are the
// same sizes.
assert((SrcEltVT == MVT::f32 || SrcEltVT == MVT::f64) && "Unknown FP VT!");
EVT IntVT = EVT::getIntegerVT(*DAG.getContext(), SrcEltVT.getSizeInBits());
BV = ConstantFoldBITCASTofBUILD_VECTOR(BV, IntVT).getNode();
SrcEltVT = IntVT;
}
// Now we know the input is an integer vector. If the output is a FP type,
// convert to integer first, then to FP of the right size.
if (DstEltVT.isFloatingPoint()) {
assert((DstEltVT == MVT::f32 || DstEltVT == MVT::f64) && "Unknown FP VT!");
EVT TmpVT = EVT::getIntegerVT(*DAG.getContext(), DstEltVT.getSizeInBits());
SDNode *Tmp = ConstantFoldBITCASTofBUILD_VECTOR(BV, TmpVT).getNode();
// Next, convert to FP elements of the same size.
return ConstantFoldBITCASTofBUILD_VECTOR(Tmp, DstEltVT);
}
// Okay, we know the src/dst types are both integers of differing types.
// Handling growing first.
assert(SrcEltVT.isInteger() && DstEltVT.isInteger());
if (SrcBitSize < DstBitSize) {
unsigned NumInputsPerOutput = DstBitSize/SrcBitSize;
SmallVector<SDValue, 8> Ops;
for (unsigned i = 0, e = BV->getNumOperands(); i != e;
i += NumInputsPerOutput) {
bool isLE = TLI.isLittleEndian();
APInt NewBits = APInt(DstBitSize, 0);
bool EltIsUndef = true;
for (unsigned j = 0; j != NumInputsPerOutput; ++j) {
// Shift the previously computed bits over.
NewBits <<= SrcBitSize;
SDValue Op = BV->getOperand(i+ (isLE ? (NumInputsPerOutput-j-1) : j));
if (Op.getOpcode() == ISD::UNDEF) continue;
EltIsUndef = false;
NewBits |= cast<ConstantSDNode>(Op)->getAPIntValue().
zextOrTrunc(SrcBitSize).zext(DstBitSize);
}
if (EltIsUndef)
Ops.push_back(DAG.getUNDEF(DstEltVT));
else
Ops.push_back(DAG.getConstant(NewBits, DstEltVT));
}
EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT, Ops.size());
return DAG.getNode(ISD::BUILD_VECTOR, BV->getDebugLoc(), VT,
&Ops[0], Ops.size());
}
// Finally, this must be the case where we are shrinking elements: each input
// turns into multiple outputs.
bool isS2V = ISD::isScalarToVector(BV);
unsigned NumOutputsPerInput = SrcBitSize/DstBitSize;
EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT,
NumOutputsPerInput*BV->getNumOperands());
SmallVector<SDValue, 8> Ops;
for (unsigned i = 0, e = BV->getNumOperands(); i != e; ++i) {
if (BV->getOperand(i).getOpcode() == ISD::UNDEF) {
for (unsigned j = 0; j != NumOutputsPerInput; ++j)
Ops.push_back(DAG.getUNDEF(DstEltVT));
continue;
}
APInt OpVal = cast<ConstantSDNode>(BV->getOperand(i))->
getAPIntValue().zextOrTrunc(SrcBitSize);
for (unsigned j = 0; j != NumOutputsPerInput; ++j) {
APInt ThisVal = OpVal.trunc(DstBitSize);
Ops.push_back(DAG.getConstant(ThisVal, DstEltVT));
if (isS2V && i == 0 && j == 0 && ThisVal.zext(SrcBitSize) == OpVal)
// Simply turn this into a SCALAR_TO_VECTOR of the new type.
return DAG.getNode(ISD::SCALAR_TO_VECTOR, BV->getDebugLoc(), VT,
Ops[0]);
OpVal = OpVal.lshr(DstBitSize);
}
// For big endian targets, swap the order of the pieces of each element.
if (TLI.isBigEndian())
std::reverse(Ops.end()-NumOutputsPerInput, Ops.end());
}
return DAG.getNode(ISD::BUILD_VECTOR, BV->getDebugLoc(), VT,
&Ops[0], Ops.size());
}
SDValue DAGCombiner::visitFADD(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
EVT VT = N->getValueType(0);
// fold vector ops
if (VT.isVector()) {
SDValue FoldedVOp = SimplifyVBinOp(N);
if (FoldedVOp.getNode()) return FoldedVOp;
}
// fold (fadd c1, c2) -> (fadd c1, c2)
if (N0CFP && N1CFP && VT != MVT::ppcf128)
return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0, N1);
// canonicalize constant to RHS
if (N0CFP && !N1CFP)
return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N1, N0);
// fold (fadd A, 0) -> A
if (UnsafeFPMath && N1CFP && N1CFP->getValueAPF().isZero())
return N0;
// fold (fadd A, (fneg B)) -> (fsub A, B)
if (isNegatibleForFree(N1, LegalOperations) == 2)
return DAG.getNode(ISD::FSUB, N->getDebugLoc(), VT, N0,
GetNegatedExpression(N1, DAG, LegalOperations));
// fold (fadd (fneg A), B) -> (fsub B, A)
if (isNegatibleForFree(N0, LegalOperations) == 2)
return DAG.getNode(ISD::FSUB, N->getDebugLoc(), VT, N1,
GetNegatedExpression(N0, DAG, LegalOperations));
// If allowed, fold (fadd (fadd x, c1), c2) -> (fadd x, (fadd c1, c2))
if (UnsafeFPMath && N1CFP && N0.getOpcode() == ISD::FADD &&
N0.getNode()->hasOneUse() && isa<ConstantFPSDNode>(N0.getOperand(1)))
return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0.getOperand(0),
DAG.getNode(ISD::FADD, N->getDebugLoc(), VT,
N0.getOperand(1), N1));
return SDValue();
}
SDValue DAGCombiner::visitFSUB(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
EVT VT = N->getValueType(0);
// fold vector ops
if (VT.isVector()) {
SDValue FoldedVOp = SimplifyVBinOp(N);
if (FoldedVOp.getNode()) return FoldedVOp;
}
// fold (fsub c1, c2) -> c1-c2
if (N0CFP && N1CFP && VT != MVT::ppcf128)
return DAG.getNode(ISD::FSUB, N->getDebugLoc(), VT, N0, N1);
// fold (fsub A, 0) -> A
if (UnsafeFPMath && N1CFP && N1CFP->getValueAPF().isZero())
return N0;
// fold (fsub 0, B) -> -B
if (UnsafeFPMath && N0CFP && N0CFP->getValueAPF().isZero()) {
if (isNegatibleForFree(N1, LegalOperations))
return GetNegatedExpression(N1, DAG, LegalOperations);
if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT))
return DAG.getNode(ISD::FNEG, N->getDebugLoc(), VT, N1);
}
// fold (fsub A, (fneg B)) -> (fadd A, B)
if (isNegatibleForFree(N1, LegalOperations))
return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0,
GetNegatedExpression(N1, DAG, LegalOperations));
return SDValue();
}
SDValue DAGCombiner::visitFMUL(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
EVT VT = N->getValueType(0);
// fold vector ops
if (VT.isVector()) {
SDValue FoldedVOp = SimplifyVBinOp(N);
if (FoldedVOp.getNode()) return FoldedVOp;
}
// fold (fmul c1, c2) -> c1*c2
if (N0CFP && N1CFP && VT != MVT::ppcf128)
return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, N0, N1);
// canonicalize constant to RHS
if (N0CFP && !N1CFP)
return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, N1, N0);
// fold (fmul A, 0) -> 0
if (UnsafeFPMath && N1CFP && N1CFP->getValueAPF().isZero())
return N1;
// fold (fmul A, 0) -> 0, vector edition.
if (UnsafeFPMath && ISD::isBuildVectorAllZeros(N1.getNode()))
return N1;
// fold (fmul X, 2.0) -> (fadd X, X)
if (N1CFP && N1CFP->isExactlyValue(+2.0))
return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0, N0);
// fold (fmul X, -1.0) -> (fneg X)
if (N1CFP && N1CFP->isExactlyValue(-1.0))
if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT))
return DAG.getNode(ISD::FNEG, N->getDebugLoc(), VT, N0);
// fold (fmul (fneg X), (fneg Y)) -> (fmul X, Y)
if (char LHSNeg = isNegatibleForFree(N0, LegalOperations)) {
if (char RHSNeg = isNegatibleForFree(N1, LegalOperations)) {
// Both can be negated for free, check to see if at least one is cheaper
// negated.
if (LHSNeg == 2 || RHSNeg == 2)
return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT,
GetNegatedExpression(N0, DAG, LegalOperations),
GetNegatedExpression(N1, DAG, LegalOperations));
}
}
// If allowed, fold (fmul (fmul x, c1), c2) -> (fmul x, (fmul c1, c2))
if (UnsafeFPMath && N1CFP && N0.getOpcode() == ISD::FMUL &&
N0.getNode()->hasOneUse() && isa<ConstantFPSDNode>(N0.getOperand(1)))
return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, N0.getOperand(0),
DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT,
N0.getOperand(1), N1));
return SDValue();
}
SDValue DAGCombiner::visitFDIV(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
EVT VT = N->getValueType(0);
// fold vector ops
if (VT.isVector()) {
SDValue FoldedVOp = SimplifyVBinOp(N);
if (FoldedVOp.getNode()) return FoldedVOp;
}
// fold (fdiv c1, c2) -> c1/c2
if (N0CFP && N1CFP && VT != MVT::ppcf128)
return DAG.getNode(ISD::FDIV, N->getDebugLoc(), VT, N0, N1);
// (fdiv (fneg X), (fneg Y)) -> (fdiv X, Y)
if (char LHSNeg = isNegatibleForFree(N0, LegalOperations)) {
if (char RHSNeg = isNegatibleForFree(N1, LegalOperations)) {
// Both can be negated for free, check to see if at least one is cheaper
// negated.
if (LHSNeg == 2 || RHSNeg == 2)
return DAG.getNode(ISD::FDIV, N->getDebugLoc(), VT,
GetNegatedExpression(N0, DAG, LegalOperations),
GetNegatedExpression(N1, DAG, LegalOperations));
}
}
return SDValue();
}
SDValue DAGCombiner::visitFREM(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
EVT VT = N->getValueType(0);
// fold (frem c1, c2) -> fmod(c1,c2)
if (N0CFP && N1CFP && VT != MVT::ppcf128)
return DAG.getNode(ISD::FREM, N->getDebugLoc(), VT, N0, N1);
return SDValue();
}
SDValue DAGCombiner::visitFCOPYSIGN(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
EVT VT = N->getValueType(0);
if (N0CFP && N1CFP && VT != MVT::ppcf128) // Constant fold
return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT, N0, N1);
if (N1CFP) {
const APFloat& V = N1CFP->getValueAPF();
// copysign(x, c1) -> fabs(x) iff ispos(c1)
// copysign(x, c1) -> fneg(fabs(x)) iff isneg(c1)
if (!V.isNegative()) {
if (!LegalOperations || TLI.isOperationLegal(ISD::FABS, VT))
return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0);
} else {
if (!LegalOperations || TLI.isOperationLegal(ISD::FNEG, VT))
return DAG.getNode(ISD::FNEG, N->getDebugLoc(), VT,
DAG.getNode(ISD::FABS, N0.getDebugLoc(), VT, N0));
}
}
// copysign(fabs(x), y) -> copysign(x, y)
// copysign(fneg(x), y) -> copysign(x, y)
// copysign(copysign(x,z), y) -> copysign(x, y)
if (N0.getOpcode() == ISD::FABS || N0.getOpcode() == ISD::FNEG ||
N0.getOpcode() == ISD::FCOPYSIGN)
return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT,
N0.getOperand(0), N1);
// copysign(x, abs(y)) -> abs(x)
if (N1.getOpcode() == ISD::FABS)
return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0);
// copysign(x, copysign(y,z)) -> copysign(x, z)
if (N1.getOpcode() == ISD::FCOPYSIGN)
return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT,
N0, N1.getOperand(1));
// copysign(x, fp_extend(y)) -> copysign(x, y)
// copysign(x, fp_round(y)) -> copysign(x, y)
if (N1.getOpcode() == ISD::FP_EXTEND || N1.getOpcode() == ISD::FP_ROUND)
return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT,
N0, N1.getOperand(0));
return SDValue();
}
SDValue DAGCombiner::visitSINT_TO_FP(SDNode *N) {
SDValue N0 = N->getOperand(0);
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
EVT VT = N->getValueType(0);
EVT OpVT = N0.getValueType();
// fold (sint_to_fp c1) -> c1fp
if (N0C && OpVT != MVT::ppcf128 &&
// ...but only if the target supports immediate floating-point values
(Level == llvm::Unrestricted ||
TLI.isOperationLegalOrCustom(llvm::ISD::ConstantFP, VT)))
return DAG.getNode(ISD::SINT_TO_FP, N->getDebugLoc(), VT, N0);
// If the input is a legal type, and SINT_TO_FP is not legal on this target,
// but UINT_TO_FP is legal on this target, try to convert.
if (!TLI.isOperationLegalOrCustom(ISD::SINT_TO_FP, OpVT) &&
TLI.isOperationLegalOrCustom(ISD::UINT_TO_FP, OpVT)) {
// If the sign bit is known to be zero, we can change this to UINT_TO_FP.
if (DAG.SignBitIsZero(N0))
return DAG.getNode(ISD::UINT_TO_FP, N->getDebugLoc(), VT, N0);
}
return SDValue();
}
SDValue DAGCombiner::visitUINT_TO_FP(SDNode *N) {
SDValue N0 = N->getOperand(0);
ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0);
EVT VT = N->getValueType(0);
EVT OpVT = N0.getValueType();
// fold (uint_to_fp c1) -> c1fp
if (N0C && OpVT != MVT::ppcf128 &&
// ...but only if the target supports immediate floating-point values
(Level == llvm::Unrestricted ||
TLI.isOperationLegalOrCustom(llvm::ISD::ConstantFP, VT)))
return DAG.getNode(ISD::UINT_TO_FP, N->getDebugLoc(), VT, N0);
// If the input is a legal type, and UINT_TO_FP is not legal on this target,
// but SINT_TO_FP is legal on this target, try to convert.
if (!TLI.isOperationLegalOrCustom(ISD::UINT_TO_FP, OpVT) &&
TLI.isOperationLegalOrCustom(ISD::SINT_TO_FP, OpVT)) {
// If the sign bit is known to be zero, we can change this to SINT_TO_FP.
if (DAG.SignBitIsZero(N0))
return DAG.getNode(ISD::SINT_TO_FP, N->getDebugLoc(), VT, N0);
}
return SDValue();
}
SDValue DAGCombiner::visitFP_TO_SINT(SDNode *N) {
SDValue N0 = N->getOperand(0);
ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
EVT VT = N->getValueType(0);
// fold (fp_to_sint c1fp) -> c1
if (N0CFP)
return DAG.getNode(ISD::FP_TO_SINT, N->getDebugLoc(), VT, N0);
return SDValue();
}
SDValue DAGCombiner::visitFP_TO_UINT(SDNode *N) {
SDValue N0 = N->getOperand(0);
ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
EVT VT = N->getValueType(0);
// fold (fp_to_uint c1fp) -> c1
if (N0CFP && VT != MVT::ppcf128)
return DAG.getNode(ISD::FP_TO_UINT, N->getDebugLoc(), VT, N0);
return SDValue();
}
SDValue DAGCombiner::visitFP_ROUND(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
EVT VT = N->getValueType(0);
// fold (fp_round c1fp) -> c1fp
if (N0CFP && N0.getValueType() != MVT::ppcf128)
return DAG.getNode(ISD::FP_ROUND, N->getDebugLoc(), VT, N0, N1);
// fold (fp_round (fp_extend x)) -> x
if (N0.getOpcode() == ISD::FP_EXTEND && VT == N0.getOperand(0).getValueType())
return N0.getOperand(0);
// fold (fp_round (fp_round x)) -> (fp_round x)
if (N0.getOpcode() == ISD::FP_ROUND) {
// This is a value preserving truncation if both round's are.
bool IsTrunc = N->getConstantOperandVal(1) == 1 &&
N0.getNode()->getConstantOperandVal(1) == 1;
return DAG.getNode(ISD::FP_ROUND, N->getDebugLoc(), VT, N0.getOperand(0),
DAG.getIntPtrConstant(IsTrunc));
}
// fold (fp_round (copysign X, Y)) -> (copysign (fp_round X), Y)
if (N0.getOpcode() == ISD::FCOPYSIGN && N0.getNode()->hasOneUse()) {
SDValue Tmp = DAG.getNode(ISD::FP_ROUND, N0.getDebugLoc(), VT,
N0.getOperand(0), N1);
AddToWorkList(Tmp.getNode());
return DAG.getNode(ISD::FCOPYSIGN, N->getDebugLoc(), VT,
Tmp, N0.getOperand(1));
}
return SDValue();
}
SDValue DAGCombiner::visitFP_ROUND_INREG(SDNode *N) {
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
EVT EVT = cast<VTSDNode>(N->getOperand(1))->getVT();
ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
// fold (fp_round_inreg c1fp) -> c1fp
if (N0CFP && isTypeLegal(EVT)) {
SDValue Round = DAG.getConstantFP(*N0CFP->getConstantFPValue(), EVT);
return DAG.getNode(ISD::FP_EXTEND, N->getDebugLoc(), VT, Round);
}
return SDValue();
}
SDValue DAGCombiner::visitFP_EXTEND(SDNode *N) {
SDValue N0 = N->getOperand(0);
ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
EVT VT = N->getValueType(0);
// If this is fp_round(fpextend), don't fold it, allow ourselves to be folded.
if (N->hasOneUse() &&
N->use_begin()->getOpcode() == ISD::FP_ROUND)
return SDValue();
// fold (fp_extend c1fp) -> c1fp
if (N0CFP && VT != MVT::ppcf128)
return DAG.getNode(ISD::FP_EXTEND, N->getDebugLoc(), VT, N0);
// Turn fp_extend(fp_round(X, 1)) -> x since the fp_round doesn't affect the
// value of X.
if (N0.getOpcode() == ISD::FP_ROUND
&& N0.getNode()->getConstantOperandVal(1) == 1) {
SDValue In = N0.getOperand(0);
if (In.getValueType() == VT) return In;
if (VT.bitsLT(In.getValueType()))
return DAG.getNode(ISD::FP_ROUND, N->getDebugLoc(), VT,
In, N0.getOperand(1));
return DAG.getNode(ISD::FP_EXTEND, N->getDebugLoc(), VT, In);
}
// fold (fpext (load x)) -> (fpext (fptrunc (extload x)))
if (ISD::isNON_EXTLoad(N0.getNode()) && N0.hasOneUse() &&
((!LegalOperations && !cast<LoadSDNode>(N0)->isVolatile()) ||
TLI.isLoadExtLegal(ISD::EXTLOAD, N0.getValueType()))) {
LoadSDNode *LN0 = cast<LoadSDNode>(N0);
SDValue ExtLoad = DAG.getExtLoad(ISD::EXTLOAD, N->getDebugLoc(), VT,
LN0->getChain(),
LN0->getBasePtr(), LN0->getPointerInfo(),
N0.getValueType(),
LN0->isVolatile(), LN0->isNonTemporal(),
LN0->getAlignment());
CombineTo(N, ExtLoad);
CombineTo(N0.getNode(),
DAG.getNode(ISD::FP_ROUND, N0.getDebugLoc(),
N0.getValueType(), ExtLoad, DAG.getIntPtrConstant(1)),
ExtLoad.getValue(1));
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
return SDValue();
}
SDValue DAGCombiner::visitFNEG(SDNode *N) {
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
if (isNegatibleForFree(N0, LegalOperations))
return GetNegatedExpression(N0, DAG, LegalOperations);
// Transform fneg(bitconvert(x)) -> bitconvert(x^sign) to avoid loading
// constant pool values.
if (N0.getOpcode() == ISD::BITCAST &&
!VT.isVector() &&
N0.getNode()->hasOneUse() &&
N0.getOperand(0).getValueType().isInteger()) {
SDValue Int = N0.getOperand(0);
EVT IntVT = Int.getValueType();
if (IntVT.isInteger() && !IntVT.isVector()) {
Int = DAG.getNode(ISD::XOR, N0.getDebugLoc(), IntVT, Int,
DAG.getConstant(APInt::getSignBit(IntVT.getSizeInBits()), IntVT));
AddToWorkList(Int.getNode());
return DAG.getNode(ISD::BITCAST, N->getDebugLoc(),
VT, Int);
}
}
return SDValue();
}
SDValue DAGCombiner::visitFABS(SDNode *N) {
SDValue N0 = N->getOperand(0);
ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
EVT VT = N->getValueType(0);
// fold (fabs c1) -> fabs(c1)
if (N0CFP && VT != MVT::ppcf128)
return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0);
// fold (fabs (fabs x)) -> (fabs x)
if (N0.getOpcode() == ISD::FABS)
return N->getOperand(0);
// fold (fabs (fneg x)) -> (fabs x)
// fold (fabs (fcopysign x, y)) -> (fabs x)
if (N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FCOPYSIGN)
return DAG.getNode(ISD::FABS, N->getDebugLoc(), VT, N0.getOperand(0));
// Transform fabs(bitconvert(x)) -> bitconvert(x&~sign) to avoid loading
// constant pool values.
if (N0.getOpcode() == ISD::BITCAST && N0.getNode()->hasOneUse() &&
N0.getOperand(0).getValueType().isInteger() &&
!N0.getOperand(0).getValueType().isVector()) {
SDValue Int = N0.getOperand(0);
EVT IntVT = Int.getValueType();
if (IntVT.isInteger() && !IntVT.isVector()) {
Int = DAG.getNode(ISD::AND, N0.getDebugLoc(), IntVT, Int,
DAG.getConstant(~APInt::getSignBit(IntVT.getSizeInBits()), IntVT));
AddToWorkList(Int.getNode());
return DAG.getNode(ISD::BITCAST, N->getDebugLoc(),
N->getValueType(0), Int);
}
}
return SDValue();
}
SDValue DAGCombiner::visitBRCOND(SDNode *N) {
SDValue Chain = N->getOperand(0);
SDValue N1 = N->getOperand(1);
SDValue N2 = N->getOperand(2);
// If N is a constant we could fold this into a fallthrough or unconditional
// branch. However that doesn't happen very often in normal code, because
// Instcombine/SimplifyCFG should have handled the available opportunities.
// If we did this folding here, it would be necessary to update the
// MachineBasicBlock CFG, which is awkward.
// fold a brcond with a setcc condition into a BR_CC node if BR_CC is legal
// on the target.
if (N1.getOpcode() == ISD::SETCC &&
TLI.isOperationLegalOrCustom(ISD::BR_CC, MVT::Other)) {
return DAG.getNode(ISD::BR_CC, N->getDebugLoc(), MVT::Other,
Chain, N1.getOperand(2),
N1.getOperand(0), N1.getOperand(1), N2);
}
if ((N1.hasOneUse() && N1.getOpcode() == ISD::SRL) ||
((N1.getOpcode() == ISD::TRUNCATE && N1.hasOneUse()) &&
(N1.getOperand(0).hasOneUse() &&
N1.getOperand(0).getOpcode() == ISD::SRL))) {
SDNode *Trunc = 0;
if (N1.getOpcode() == ISD::TRUNCATE) {
// Look pass the truncate.
Trunc = N1.getNode();
N1 = N1.getOperand(0);
}
// Match this pattern so that we can generate simpler code:
//
// %a = ...
// %b = and i32 %a, 2
// %c = srl i32 %b, 1
// brcond i32 %c ...
//
// into
//
// %a = ...
// %b = and i32 %a, 2
// %c = setcc eq %b, 0
// brcond %c ...
//
// This applies only when the AND constant value has one bit set and the
// SRL constant is equal to the log2 of the AND constant. The back-end is
// smart enough to convert the result into a TEST/JMP sequence.
SDValue Op0 = N1.getOperand(0);
SDValue Op1 = N1.getOperand(1);
if (Op0.getOpcode() == ISD::AND &&
Op1.getOpcode() == ISD::Constant) {
SDValue AndOp1 = Op0.getOperand(1);
if (AndOp1.getOpcode() == ISD::Constant) {
const APInt &AndConst = cast<ConstantSDNode>(AndOp1)->getAPIntValue();
if (AndConst.isPowerOf2() &&
cast<ConstantSDNode>(Op1)->getAPIntValue()==AndConst.logBase2()) {
SDValue SetCC =
DAG.getSetCC(N->getDebugLoc(),
TLI.getSetCCResultType(Op0.getValueType()),
Op0, DAG.getConstant(0, Op0.getValueType()),
ISD::SETNE);
SDValue NewBRCond = DAG.getNode(ISD::BRCOND, N->getDebugLoc(),
MVT::Other, Chain, SetCC, N2);
// Don't add the new BRCond into the worklist or else SimplifySelectCC
// will convert it back to (X & C1) >> C2.
CombineTo(N, NewBRCond, false);
// Truncate is dead.
if (Trunc) {
removeFromWorkList(Trunc);
DAG.DeleteNode(Trunc);
}
// Replace the uses of SRL with SETCC
WorkListRemover DeadNodes(*this);
DAG.ReplaceAllUsesOfValueWith(N1, SetCC, &DeadNodes);
removeFromWorkList(N1.getNode());
DAG.DeleteNode(N1.getNode());
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
}
}
if (Trunc)
// Restore N1 if the above transformation doesn't match.
N1 = N->getOperand(1);
}
// Transform br(xor(x, y)) -> br(x != y)
// Transform br(xor(xor(x,y), 1)) -> br (x == y)
if (N1.hasOneUse() && N1.getOpcode() == ISD::XOR) {
SDNode *TheXor = N1.getNode();
SDValue Op0 = TheXor->getOperand(0);
SDValue Op1 = TheXor->getOperand(1);
if (Op0.getOpcode() == Op1.getOpcode()) {
// Avoid missing important xor optimizations.
SDValue Tmp = visitXOR(TheXor);
if (Tmp.getNode() && Tmp.getNode() != TheXor) {
DEBUG(dbgs() << "\nReplacing.8 ";
TheXor->dump(&DAG);
dbgs() << "\nWith: ";
Tmp.getNode()->dump(&DAG);
dbgs() << '\n');
WorkListRemover DeadNodes(*this);
DAG.ReplaceAllUsesOfValueWith(N1, Tmp, &DeadNodes);
removeFromWorkList(TheXor);
DAG.DeleteNode(TheXor);
return DAG.getNode(ISD::BRCOND, N->getDebugLoc(),
MVT::Other, Chain, Tmp, N2);
}
}
if (Op0.getOpcode() != ISD::SETCC && Op1.getOpcode() != ISD::SETCC) {
bool Equal = false;
if (ConstantSDNode *RHSCI = dyn_cast<ConstantSDNode>(Op0))
if (RHSCI->getAPIntValue() == 1 && Op0.hasOneUse() &&
Op0.getOpcode() == ISD::XOR) {
TheXor = Op0.getNode();
Equal = true;
}
EVT SetCCVT = N1.getValueType();
if (LegalTypes)
SetCCVT = TLI.getSetCCResultType(SetCCVT);
SDValue SetCC = DAG.getSetCC(TheXor->getDebugLoc(),
SetCCVT,
Op0, Op1,
Equal ? ISD::SETEQ : ISD::SETNE);
// Replace the uses of XOR with SETCC
WorkListRemover DeadNodes(*this);
DAG.ReplaceAllUsesOfValueWith(N1, SetCC, &DeadNodes);
removeFromWorkList(N1.getNode());
DAG.DeleteNode(N1.getNode());
return DAG.getNode(ISD::BRCOND, N->getDebugLoc(),
MVT::Other, Chain, SetCC, N2);
}
}
return SDValue();
}
// Operand List for BR_CC: Chain, CondCC, CondLHS, CondRHS, DestBB.
//
SDValue DAGCombiner::visitBR_CC(SDNode *N) {
CondCodeSDNode *CC = cast<CondCodeSDNode>(N->getOperand(1));
SDValue CondLHS = N->getOperand(2), CondRHS = N->getOperand(3);
// If N is a constant we could fold this into a fallthrough or unconditional
// branch. However that doesn't happen very often in normal code, because
// Instcombine/SimplifyCFG should have handled the available opportunities.
// If we did this folding here, it would be necessary to update the
// MachineBasicBlock CFG, which is awkward.
// Use SimplifySetCC to simplify SETCC's.
SDValue Simp = SimplifySetCC(TLI.getSetCCResultType(CondLHS.getValueType()),
CondLHS, CondRHS, CC->get(), N->getDebugLoc(),
false);
if (Simp.getNode()) AddToWorkList(Simp.getNode());
// fold to a simpler setcc
if (Simp.getNode() && Simp.getOpcode() == ISD::SETCC)
return DAG.getNode(ISD::BR_CC, N->getDebugLoc(), MVT::Other,
N->getOperand(0), Simp.getOperand(2),
Simp.getOperand(0), Simp.getOperand(1),
N->getOperand(4));
return SDValue();
}
/// CombineToPreIndexedLoadStore - Try turning a load / store into a
/// pre-indexed load / store when the base pointer is an add or subtract
/// and it has other uses besides the load / store. After the
/// transformation, the new indexed load / store has effectively folded
/// the add / subtract in and all of its other uses are redirected to the
/// new load / store.
bool DAGCombiner::CombineToPreIndexedLoadStore(SDNode *N) {
if (!LegalOperations)
return false;
bool isLoad = true;
SDValue Ptr;
EVT VT;
if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
if (LD->isIndexed())
return false;
VT = LD->getMemoryVT();
if (!TLI.isIndexedLoadLegal(ISD::PRE_INC, VT) &&
!TLI.isIndexedLoadLegal(ISD::PRE_DEC, VT))
return false;
Ptr = LD->getBasePtr();
} else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) {
if (ST->isIndexed())
return false;
VT = ST->getMemoryVT();
if (!TLI.isIndexedStoreLegal(ISD::PRE_INC, VT) &&
!TLI.isIndexedStoreLegal(ISD::PRE_DEC, VT))
return false;
Ptr = ST->getBasePtr();
isLoad = false;
} else {
return false;
}
// If the pointer is not an add/sub, or if it doesn't have multiple uses, bail
// out. There is no reason to make this a preinc/predec.
if ((Ptr.getOpcode() != ISD::ADD && Ptr.getOpcode() != ISD::SUB) ||
Ptr.getNode()->hasOneUse())
return false;
// Ask the target to do addressing mode selection.
SDValue BasePtr;
SDValue Offset;
ISD::MemIndexedMode AM = ISD::UNINDEXED;
if (!TLI.getPreIndexedAddressParts(N, BasePtr, Offset, AM, DAG))
return false;
// Don't create a indexed load / store with zero offset.
if (isa<ConstantSDNode>(Offset) &&
cast<ConstantSDNode>(Offset)->isNullValue())
return false;
// Try turning it into a pre-indexed load / store except when:
// 1) The new base ptr is a frame index.
// 2) If N is a store and the new base ptr is either the same as or is a
// predecessor of the value being stored.
// 3) Another use of old base ptr is a predecessor of N. If ptr is folded
// that would create a cycle.
// 4) All uses are load / store ops that use it as old base ptr.
// Check #1. Preinc'ing a frame index would require copying the stack pointer
// (plus the implicit offset) to a register to preinc anyway.
if (isa<FrameIndexSDNode>(BasePtr) || isa<RegisterSDNode>(BasePtr))
return false;
// Check #2.
if (!isLoad) {
SDValue Val = cast<StoreSDNode>(N)->getValue();
if (Val == BasePtr || BasePtr.getNode()->isPredecessorOf(Val.getNode()))
return false;
}
// Now check for #3 and #4.
bool RealUse = false;
// Caches for hasPredecessorHelper
SmallPtrSet<const SDNode *, 32> Visited;
SmallVector<const SDNode *, 16> Worklist;
for (SDNode::use_iterator I = Ptr.getNode()->use_begin(),
E = Ptr.getNode()->use_end(); I != E; ++I) {
SDNode *Use = *I;
if (Use == N)
continue;
if (N->hasPredecessorHelper(Use, Visited, Worklist))
return false;
if (!((Use->getOpcode() == ISD::LOAD &&
cast<LoadSDNode>(Use)->getBasePtr() == Ptr) ||
(Use->getOpcode() == ISD::STORE &&
cast<StoreSDNode>(Use)->getBasePtr() == Ptr)))
RealUse = true;
}
if (!RealUse)
return false;
SDValue Result;
if (isLoad)
Result = DAG.getIndexedLoad(SDValue(N,0), N->getDebugLoc(),
BasePtr, Offset, AM);
else
Result = DAG.getIndexedStore(SDValue(N,0), N->getDebugLoc(),
BasePtr, Offset, AM);
++PreIndexedNodes;
++NodesCombined;
DEBUG(dbgs() << "\nReplacing.4 ";
N->dump(&DAG);
dbgs() << "\nWith: ";
Result.getNode()->dump(&DAG);
dbgs() << '\n');
WorkListRemover DeadNodes(*this);
if (isLoad) {
DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(0),
&DeadNodes);
DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Result.getValue(2),
&DeadNodes);
} else {
DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(1),
&DeadNodes);
}
// Finally, since the node is now dead, remove it from the graph.
DAG.DeleteNode(N);
// Replace the uses of Ptr with uses of the updated base value.
DAG.ReplaceAllUsesOfValueWith(Ptr, Result.getValue(isLoad ? 1 : 0),
&DeadNodes);
removeFromWorkList(Ptr.getNode());
DAG.DeleteNode(Ptr.getNode());
return true;
}
/// CombineToPostIndexedLoadStore - Try to combine a load / store with a
/// add / sub of the base pointer node into a post-indexed load / store.
/// The transformation folded the add / subtract into the new indexed
/// load / store effectively and all of its uses are redirected to the
/// new load / store.
bool DAGCombiner::CombineToPostIndexedLoadStore(SDNode *N) {
if (!LegalOperations)
return false;
bool isLoad = true;
SDValue Ptr;
EVT VT;
if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
if (LD->isIndexed())
return false;
VT = LD->getMemoryVT();
if (!TLI.isIndexedLoadLegal(ISD::POST_INC, VT) &&
!TLI.isIndexedLoadLegal(ISD::POST_DEC, VT))
return false;
Ptr = LD->getBasePtr();
} else if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) {
if (ST->isIndexed())
return false;
VT = ST->getMemoryVT();
if (!TLI.isIndexedStoreLegal(ISD::POST_INC, VT) &&
!TLI.isIndexedStoreLegal(ISD::POST_DEC, VT))
return false;
Ptr = ST->getBasePtr();
isLoad = false;
} else {
return false;
}
if (Ptr.getNode()->hasOneUse())
return false;
for (SDNode::use_iterator I = Ptr.getNode()->use_begin(),
E = Ptr.getNode()->use_end(); I != E; ++I) {
SDNode *Op = *I;
if (Op == N ||
(Op->getOpcode() != ISD::ADD && Op->getOpcode() != ISD::SUB))
continue;
SDValue BasePtr;
SDValue Offset;
ISD::MemIndexedMode AM = ISD::UNINDEXED;
if (TLI.getPostIndexedAddressParts(N, Op, BasePtr, Offset, AM, DAG)) {
// Don't create a indexed load / store with zero offset.
if (isa<ConstantSDNode>(Offset) &&
cast<ConstantSDNode>(Offset)->isNullValue())
continue;
// Try turning it into a post-indexed load / store except when
// 1) All uses are load / store ops that use it as base ptr.
// 2) Op must be independent of N, i.e. Op is neither a predecessor
// nor a successor of N. Otherwise, if Op is folded that would
// create a cycle.
if (isa<FrameIndexSDNode>(BasePtr) || isa<RegisterSDNode>(BasePtr))
continue;
// Check for #1.
bool TryNext = false;
for (SDNode::use_iterator II = BasePtr.getNode()->use_begin(),
EE = BasePtr.getNode()->use_end(); II != EE; ++II) {
SDNode *Use = *II;
if (Use == Ptr.getNode())
continue;
// If all the uses are load / store addresses, then don't do the
// transformation.
if (Use->getOpcode() == ISD::ADD || Use->getOpcode() == ISD::SUB){
bool RealUse = false;
for (SDNode::use_iterator III = Use->use_begin(),
EEE = Use->use_end(); III != EEE; ++III) {
SDNode *UseUse = *III;
if (!((UseUse->getOpcode() == ISD::LOAD &&
cast<LoadSDNode>(UseUse)->getBasePtr().getNode() == Use) ||
(UseUse->getOpcode() == ISD::STORE &&
cast<StoreSDNode>(UseUse)->getBasePtr().getNode() == Use)))
RealUse = true;
}
if (!RealUse) {
TryNext = true;
break;
}
}
}
if (TryNext)
continue;
// Check for #2
if (!Op->isPredecessorOf(N) && !N->isPredecessorOf(Op)) {
SDValue Result = isLoad
? DAG.getIndexedLoad(SDValue(N,0), N->getDebugLoc(),
BasePtr, Offset, AM)
: DAG.getIndexedStore(SDValue(N,0), N->getDebugLoc(),
BasePtr, Offset, AM);
++PostIndexedNodes;
++NodesCombined;
DEBUG(dbgs() << "\nReplacing.5 ";
N->dump(&DAG);
dbgs() << "\nWith: ";
Result.getNode()->dump(&DAG);
dbgs() << '\n');
WorkListRemover DeadNodes(*this);
if (isLoad) {
DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(0),
&DeadNodes);
DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Result.getValue(2),
&DeadNodes);
} else {
DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Result.getValue(1),
&DeadNodes);
}
// Finally, since the node is now dead, remove it from the graph.
DAG.DeleteNode(N);
// Replace the uses of Use with uses of the updated base value.
DAG.ReplaceAllUsesOfValueWith(SDValue(Op, 0),
Result.getValue(isLoad ? 1 : 0),
&DeadNodes);
removeFromWorkList(Op);
DAG.DeleteNode(Op);
return true;
}
}
}
return false;
}
SDValue DAGCombiner::visitLOAD(SDNode *N) {
LoadSDNode *LD = cast<LoadSDNode>(N);
SDValue Chain = LD->getChain();
SDValue Ptr = LD->getBasePtr();
// If load is not volatile and there are no uses of the loaded value (and
// the updated indexed value in case of indexed loads), change uses of the
// chain value into uses of the chain input (i.e. delete the dead load).
if (!LD->isVolatile()) {
if (N->getValueType(1) == MVT::Other) {
// Unindexed loads.
if (N->hasNUsesOfValue(0, 0)) {
// It's not safe to use the two value CombineTo variant here. e.g.
// v1, chain2 = load chain1, loc
// v2, chain3 = load chain2, loc
// v3 = add v2, c
// Now we replace use of chain2 with chain1. This makes the second load
// isomorphic to the one we are deleting, and thus makes this load live.
DEBUG(dbgs() << "\nReplacing.6 ";
N->dump(&DAG);
dbgs() << "\nWith chain: ";
Chain.getNode()->dump(&DAG);
dbgs() << "\n");
WorkListRemover DeadNodes(*this);
DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), Chain, &DeadNodes);
if (N->use_empty()) {
removeFromWorkList(N);
DAG.DeleteNode(N);
}
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
} else {
// Indexed loads.
assert(N->getValueType(2) == MVT::Other && "Malformed indexed loads?");
if (N->hasNUsesOfValue(0, 0) && N->hasNUsesOfValue(0, 1)) {
SDValue Undef = DAG.getUNDEF(N->getValueType(0));
DEBUG(dbgs() << "\nReplacing.7 ";
N->dump(&DAG);
dbgs() << "\nWith: ";
Undef.getNode()->dump(&DAG);
dbgs() << " and 2 other values\n");
WorkListRemover DeadNodes(*this);
DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), Undef, &DeadNodes);
DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1),
DAG.getUNDEF(N->getValueType(1)),
&DeadNodes);
DAG.ReplaceAllUsesOfValueWith(SDValue(N, 2), Chain, &DeadNodes);
removeFromWorkList(N);
DAG.DeleteNode(N);
return SDValue(N, 0); // Return N so it doesn't get rechecked!
}
}
}
// If this load is directly stored, replace the load value with the stored
// value.
// TODO: Handle store large -> read small portion.
// TODO: Handle TRUNCSTORE/LOADEXT
if (ISD::isNormalLoad(N) && !LD->isVolatile()) {
if (ISD::isNON_TRUNCStore(Chain.getNode())) {
StoreSDNode *PrevST = cast<StoreSDNode>(Chain);
if (PrevST->getBasePtr() == Ptr &&
PrevST->getValue().getValueType() == N->getValueType(0))
return CombineTo(N, Chain.getOperand(1), Chain);
}
}
// Try to infer better alignment information than the load already has.
if (OptLevel != CodeGenOpt::None && LD->isUnindexed()) {
if (unsigned Align = DAG.InferPtrAlignment(Ptr)) {
if (Align > LD->getAlignment())
return DAG.getExtLoad(LD->getExtensionType(), N->getDebugLoc(),
LD->getValueType(0),
Chain, Ptr, LD->getPointerInfo(),
LD->getMemoryVT(),
LD->isVolatile(), LD->isNonTemporal(), Align);
}
}
if (CombinerAA) {
// Walk up chain skipping non-aliasing memory nodes.
SDValue BetterChain = FindBetterChain(N, Chain);
// If there is a better chain.
if (Chain != BetterChain) {
SDValue ReplLoad;
// Replace the chain to void dependency.
if (LD->getExtensionType() == ISD::NON_EXTLOAD) {
ReplLoad = DAG.getLoad(N->getValueType(0), LD->getDebugLoc(),
BetterChain, Ptr, LD->getPointerInfo(),
LD->isVolatile(), LD->isNonTemporal(),
LD->getAlignment());
} else {
ReplLoad = DAG.getExtLoad(LD->getExtensionType(), LD->getDebugLoc(),
LD->getValueType(0),
BetterChain, Ptr, LD->getPointerInfo(),
LD->getMemoryVT(),
LD->isVolatile(),
LD->isNonTemporal(),
LD->getAlignment());
}
// Create token factor to keep old chain connected.
SDValue Token = DAG.getNode(ISD::TokenFactor, N->getDebugLoc(),
MVT::Other, Chain, ReplLoad.getValue(1));
// Make sure the new and old chains are cleaned up.
AddToWorkList(Token.getNode());
// Replace uses with load result and token factor. Don't add users
// to work list.
return CombineTo(N, ReplLoad.getValue(0), Token, false);
}
}
// Try transforming N to an indexed load.
if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N))
return SDValue(N, 0);
return SDValue();
}
/// CheckForMaskedLoad - Check to see if V is (and load (ptr), imm), where the
/// load is having specific bytes cleared out. If so, return the byte size
/// being masked out and the shift amount.
static std::pair<unsigned, unsigned>
CheckForMaskedLoad(SDValue V, SDValue Ptr, SDValue Chain) {
std::pair<unsigned, unsigned> Result(0, 0);
// Check for the structure we're looking for.
if (V->getOpcode() != ISD::AND ||
!isa<ConstantSDNode>(V->getOperand(1)) ||
!ISD::isNormalLoad(V->getOperand(0).getNode()))
return Result;
// Check the chain and pointer.
LoadSDNode *LD = cast<LoadSDNode>(V->getOperand(0));
if (LD->getBasePtr() != Ptr) return Result; // Not from same pointer.
// The store should be chained directly to the load or be an operand of a
// tokenfactor.
if (LD == Chain.getNode())
; // ok.
else if (Chain->getOpcode() != ISD::TokenFactor)
return Result; // Fail.
else {
bool isOk = false;
for (unsigned i = 0, e = Chain->getNumOperands(); i != e; ++i)
if (Chain->getOperand(i).getNode() == LD) {
isOk = true;
break;
}
if (!isOk) return Result;
}
// This only handles simple types.
if (V.getValueType() != MVT::i16 &&
V.getValueType() != MVT::i32 &&
V.getValueType() != MVT::i64)
return Result;
// Check the constant mask. Invert it so that the bits being masked out are
// 0 and the bits being kept are 1. Use getSExtValue so that leading bits
// follow the sign bit for uniformity.
uint64_t NotMask = ~cast<ConstantSDNode>(V->getOperand(1))->getSExtValue();
unsigned NotMaskLZ = CountLeadingZeros_64(NotMask);
if (NotMaskLZ & 7) return Result; // Must be multiple of a byte.
unsigned NotMaskTZ = CountTrailingZeros_64(NotMask);
if (NotMaskTZ & 7) return Result; // Must be multiple of a byte.
if (NotMaskLZ == 64) return Result; // All zero mask.
// See if we have a continuous run of bits. If so, we have 0*1+0*
if (CountTrailingOnes_64(NotMask >> NotMaskTZ)+NotMaskTZ+NotMaskLZ != 64)
return Result;
// Adjust NotMaskLZ down to be from the actual size of the int instead of i64.
if (V.getValueType() != MVT::i64 && NotMaskLZ)
NotMaskLZ -= 64-V.getValueSizeInBits();
unsigned MaskedBytes = (V.getValueSizeInBits()-NotMaskLZ-NotMaskTZ)/8;
switch (MaskedBytes) {
case 1:
case 2:
case 4: break;
default: return Result; // All one mask, or 5-byte mask.
}
// Verify that the first bit starts at a multiple of mask so that the access
// is aligned the same as the access width.
if (NotMaskTZ && NotMaskTZ/8 % MaskedBytes) return Result;
Result.first = MaskedBytes;
Result.second = NotMaskTZ/8;
return Result;
}
/// ShrinkLoadReplaceStoreWithStore - Check to see if IVal is something that
/// provides a value as specified by MaskInfo. If so, replace the specified
/// store with a narrower store of truncated IVal.
static SDNode *
ShrinkLoadReplaceStoreWithStore(const std::pair<unsigned, unsigned> &MaskInfo,
SDValue IVal, StoreSDNode *St,
DAGCombiner *DC) {
unsigned NumBytes = MaskInfo.first;
unsigned ByteShift = MaskInfo.second;
SelectionDAG &DAG = DC->getDAG();
// Check to see if IVal is all zeros in the part being masked in by the 'or'
// that uses this. If not, this is not a replacement.
APInt Mask = ~APInt::getBitsSet(IVal.getValueSizeInBits(),
ByteShift*8, (ByteShift+NumBytes)*8);
if (!DAG.MaskedValueIsZero(IVal, Mask)) return 0;
// Check that it is legal on the target to do this. It is legal if the new
// VT we're shrinking to (i8/i16/i32) is legal or we're still before type
// legalization.
MVT VT = MVT::getIntegerVT(NumBytes*8);
if (!DC->isTypeLegal(VT))
return 0;
// Okay, we can do this! Replace the 'St' store with a store of IVal that is
// shifted by ByteShift and truncated down to NumBytes.
if (ByteShift)
IVal = DAG.getNode(ISD::SRL, IVal->getDebugLoc(), IVal.getValueType(), IVal,
DAG.getConstant(ByteShift*8,
DC->getShiftAmountTy(IVal.getValueType())));
// Figure out the offset for the store and the alignment of the access.
unsigned StOffset;
unsigned NewAlign = St->getAlignment();
if (DAG.getTargetLoweringInfo().isLittleEndian())
StOffset = ByteShift;
else
StOffset = IVal.getValueType().getStoreSize() - ByteShift - NumBytes;
SDValue Ptr = St->getBasePtr();
if (StOffset) {
Ptr = DAG.getNode(ISD::ADD, IVal->getDebugLoc(), Ptr.getValueType(),
Ptr, DAG.getConstant(StOffset, Ptr.getValueType()));
NewAlign = MinAlign(NewAlign, StOffset);
}
// Truncate down to the new size.
IVal = DAG.getNode(ISD::TRUNCATE, IVal->getDebugLoc(), VT, IVal);
++OpsNarrowed;
return DAG.getStore(St->getChain(), St->getDebugLoc(), IVal, Ptr,
St->getPointerInfo().getWithOffset(StOffset),
false, false, NewAlign).getNode();
}
/// ReduceLoadOpStoreWidth - Look for sequence of load / op / store where op is
/// one of 'or', 'xor', and 'and' of immediates. If 'op' is only touching some
/// of the loaded bits, try narrowing the load and store if it would end up
/// being a win for performance or code size.
SDValue DAGCombiner::ReduceLoadOpStoreWidth(SDNode *N) {
StoreSDNode *ST = cast<StoreSDNode>(N);
if (ST->isVolatile())
return SDValue();
SDValue Chain = ST->getChain();
SDValue Value = ST->getValue();
SDValue Ptr = ST->getBasePtr();
EVT VT = Value.getValueType();
if (ST->isTruncatingStore() || VT.isVector() || !Value.hasOneUse())
return SDValue();
unsigned Opc = Value.getOpcode();
// If this is "store (or X, Y), P" and X is "(and (load P), cst)", where cst
// is a byte mask indicating a consecutive number of bytes, check to see if
// Y is known to provide just those bytes. If so, we try to replace the
// load + replace + store sequence with a single (narrower) store, which makes
// the load dead.
if (Opc == ISD::OR) {
std::pair<unsigned, unsigned> MaskedLoad;
MaskedLoad = CheckForMaskedLoad(Value.getOperand(0), Ptr, Chain);
if (MaskedLoad.first)
if (SDNode *NewST = ShrinkLoadReplaceStoreWithStore(MaskedLoad,
Value.getOperand(1), ST,this))
return SDValue(NewST, 0);
// Or is commutative, so try swapping X and Y.
MaskedLoad = CheckForMaskedLoad(Value.getOperand(1), Ptr, Chain);
if (MaskedLoad.first)
if (SDNode *NewST = ShrinkLoadReplaceStoreWithStore(MaskedLoad,
Value.getOperand(0), ST,this))
return SDValue(NewST, 0);
}
if ((Opc != ISD::OR && Opc != ISD::XOR && Opc != ISD::AND) ||
Value.getOperand(1).getOpcode() != ISD::Constant)
return SDValue();
SDValue N0 = Value.getOperand(0);
if (ISD::isNormalLoad(N0.getNode()) && N0.hasOneUse() &&
Chain == SDValue(N0.getNode(), 1)) {
LoadSDNode *LD = cast<LoadSDNode>(N0);
if (LD->getBasePtr() != Ptr ||
LD->getPointerInfo().getAddrSpace() !=
ST->getPointerInfo().getAddrSpace())
return SDValue();
// Find the type to narrow it the load / op / store to.
SDValue N1 = Value.getOperand(1);
unsigned BitWidth = N1.getValueSizeInBits();
APInt Imm = cast<ConstantSDNode>(N1)->getAPIntValue();
if (Opc == ISD::AND)
Imm ^= APInt::getAllOnesValue(BitWidth);
if (Imm == 0 || Imm.isAllOnesValue())
return SDValue();
unsigned ShAmt = Imm.countTrailingZeros();
unsigned MSB = BitWidth - Imm.countLeadingZeros() - 1;
unsigned NewBW = NextPowerOf2(MSB - ShAmt);
EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), NewBW);
while (NewBW < BitWidth &&
!(TLI.isOperationLegalOrCustom(Opc, NewVT) &&
TLI.isNarrowingProfitable(VT, NewVT))) {
NewBW = NextPowerOf2(NewBW);
NewVT = EVT::getIntegerVT(*DAG.getContext(), NewBW);
}
if (NewBW >= BitWidth)
return SDValue();
// If the lsb changed does not start at the type bitwidth boundary,
// start at the previous one.
if (ShAmt % NewBW)
ShAmt = (((ShAmt + NewBW - 1) / NewBW) * NewBW) - NewBW;
APInt Mask = APInt::getBitsSet(BitWidth, ShAmt, ShAmt + NewBW);
if ((Imm & Mask) == Imm) {
APInt NewImm = (Imm & Mask).lshr(ShAmt).trunc(NewBW);
if (Opc == ISD::AND)
NewImm ^= APInt::getAllOnesValue(NewBW);
uint64_t PtrOff = ShAmt / 8;
// For big endian targets, we need to adjust the offset to the pointer to
// load the correct bytes.
if (TLI.isBigEndian())
PtrOff = (BitWidth + 7 - NewBW) / 8 - PtrOff;
unsigned NewAlign = MinAlign(LD->getAlignment(), PtrOff);
Type *NewVTTy = NewVT.getTypeForEVT(*DAG.getContext());
if (NewAlign < TLI.getTargetData()->getABITypeAlignment(NewVTTy))
return SDValue();
SDValue NewPtr = DAG.getNode(ISD::ADD, LD->getDebugLoc(),
Ptr.getValueType(), Ptr,
DAG.getConstant(PtrOff, Ptr.getValueType()));
SDValue NewLD = DAG.getLoad(NewVT, N0.getDebugLoc(),
LD->getChain(), NewPtr,
LD->getPointerInfo().getWithOffset(PtrOff),
LD->isVolatile(), LD->isNonTemporal(),
NewAlign);
SDValue NewVal = DAG.getNode(Opc, Value.getDebugLoc(), NewVT, NewLD,
DAG.getConstant(NewImm, NewVT));
SDValue NewST = DAG.getStore(Chain, N->getDebugLoc(),
NewVal, NewPtr,
ST->getPointerInfo().getWithOffset(PtrOff),
false, false, NewAlign);
AddToWorkList(NewPtr.getNode());
AddToWorkList(NewLD.getNode());
AddToWorkList(NewVal.getNode());
WorkListRemover DeadNodes(*this);
DAG.ReplaceAllUsesOfValueWith(N0.getValue(1), NewLD.getValue(1),
&DeadNodes);
++OpsNarrowed;
return NewST;
}
}
return SDValue();
}
/// TransformFPLoadStorePair - For a given floating point load / store pair,
/// if the load value isn't used by any other operations, then consider
/// transforming the pair to integer load / store operations if the target
/// deems the transformation profitable.
SDValue DAGCombiner::TransformFPLoadStorePair(SDNode *N) {
StoreSDNode *ST = cast<StoreSDNode>(N);
SDValue Chain = ST->getChain();
SDValue Value = ST->getValue();
if (ISD::isNormalStore(ST) && ISD::isNormalLoad(Value.getNode()) &&
Value.hasOneUse() &&
Chain == SDValue(Value.getNode(), 1)) {
LoadSDNode *LD = cast<LoadSDNode>(Value);
EVT VT = LD->getMemoryVT();
if (!VT.isFloatingPoint() ||
VT != ST->getMemoryVT() ||
LD->isNonTemporal() ||
ST->isNonTemporal() ||
LD->getPointerInfo().getAddrSpace() != 0 ||
ST->getPointerInfo().getAddrSpace() != 0)
return SDValue();
EVT IntVT = EVT::getIntegerVT(*DAG.getContext(), VT.getSizeInBits());
if (!TLI.isOperationLegal(ISD::LOAD, IntVT) ||
!TLI.isOperationLegal(ISD::STORE, IntVT) ||
!TLI.isDesirableToTransformToIntegerOp(ISD::LOAD, VT) ||
!TLI.isDesirableToTransformToIntegerOp(ISD::STORE, VT))
return SDValue();
unsigned LDAlign = LD->getAlignment();
unsigned STAlign = ST->getAlignment();
Type *IntVTTy = IntVT.getTypeForEVT(*DAG.getContext());
unsigned ABIAlign = TLI.getTargetData()->getABITypeAlignment(IntVTTy);
if (LDAlign < ABIAlign || STAlign < ABIAlign)
return SDValue();
SDValue NewLD = DAG.getLoad(IntVT, Value.getDebugLoc(),
LD->getChain(), LD->getBasePtr(),
LD->getPointerInfo(),
false, false, LDAlign);
SDValue NewST = DAG.getStore(NewLD.getValue(1), N->getDebugLoc(),
NewLD, ST->getBasePtr(),
ST->getPointerInfo(),
false, false, STAlign);
AddToWorkList(NewLD.getNode());
AddToWorkList(NewST.getNode());
WorkListRemover DeadNodes(*this);
DAG.ReplaceAllUsesOfValueWith(Value.getValue(1), NewLD.getValue(1),
&DeadNodes);
++LdStFP2Int;
return NewST;
}
return SDValue();
}
SDValue DAGCombiner::visitSTORE(SDNode *N) {
StoreSDNode *ST = cast<StoreSDNode>(N);
SDValue Chain = ST->getChain();
SDValue Value = ST->getValue();
SDValue Ptr = ST->getBasePtr();
// If this is a store of a bit convert, store the input value if the
// resultant store does not need a higher alignment than the original.
if (Value.getOpcode() == ISD::BITCAST && !ST->isTruncatingStore() &&
ST->isUnindexed()) {
unsigned OrigAlign = ST->getAlignment();
EVT SVT = Value.getOperand(0).getValueType();
unsigned Align = TLI.getTargetData()->
getABITypeAlignment(SVT.getTypeForEVT(*DAG.getContext()));
if (Align <= OrigAlign &&
((!LegalOperations && !ST->isVolatile()) ||
TLI.isOperationLegalOrCustom(ISD::STORE, SVT)))
return DAG.getStore(Chain, N->getDebugLoc(), Value.getOperand(0),
Ptr, ST->getPointerInfo(), ST->isVolatile(),
ST->isNonTemporal(), OrigAlign);
}
// Turn 'store undef, Ptr' -> nothing.
if (Value.getOpcode() == ISD::UNDEF && ST->isUnindexed())
return Chain;
// Turn 'store float 1.0, Ptr' -> 'store int 0x12345678, Ptr'
if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(Value)) {
// NOTE: If the original store is volatile, this transform must not increase
// the number of stores. For example, on x86-32 an f64 can be stored in one
// processor operation but an i64 (which is not legal) requires two. So the
// transform should not be done in this case.
if (Value.getOpcode() != ISD::TargetConstantFP) {
SDValue Tmp;
switch (CFP->getValueType(0).getSimpleVT().SimpleTy) {
default: llvm_unreachable("Unknown FP type");
case MVT::f80: // We don't do this for these yet.
case MVT::f128:
case MVT::ppcf128:
break;
case MVT::f32:
if ((isTypeLegal(MVT::i32) && !LegalOperations && !ST->isVolatile()) ||
TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i32)) {
Tmp = DAG.getConstant((uint32_t)CFP->getValueAPF().
bitcastToAPInt().getZExtValue(), MVT::i32);
return DAG.getStore(Chain, N->getDebugLoc(), Tmp,
Ptr, ST->getPointerInfo(), ST->isVolatile(),
ST->isNonTemporal(), ST->getAlignment());
}
break;
case MVT::f64:
if ((TLI.isTypeLegal(MVT::i64) && !LegalOperations &&
!ST->isVolatile()) ||
TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i64)) {
Tmp = DAG.getConstant(CFP->getValueAPF().bitcastToAPInt().
getZExtValue(), MVT::i64);
return DAG.getStore(Chain, N->getDebugLoc(), Tmp,
Ptr, ST->getPointerInfo(), ST->isVolatile(),
ST->isNonTemporal(), ST->getAlignment());
}
if (!ST->isVolatile() &&
TLI.isOperationLegalOrCustom(ISD::STORE, MVT::i32)) {
// Many FP stores are not made apparent until after legalize, e.g. for
// argument passing. Since this is so common, custom legalize the
// 64-bit integer store into two 32-bit stores.
uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
SDValue Lo = DAG.getConstant(Val & 0xFFFFFFFF, MVT::i32);
SDValue Hi = DAG.getConstant(Val >> 32, MVT::i32);
if (TLI.isBigEndian()) std::swap(Lo, Hi);
unsigned Alignment = ST->getAlignment();
bool isVolatile = ST->isVolatile();
bool isNonTemporal = ST->isNonTemporal();
SDValue St0 = DAG.getStore(Chain, ST->getDebugLoc(), Lo,
Ptr, ST->getPointerInfo(),
isVolatile, isNonTemporal,
ST->getAlignment());
Ptr = DAG.getNode(ISD::ADD, N->getDebugLoc(), Ptr.getValueType(), Ptr,
DAG.getConstant(4, Ptr.getValueType()));
Alignment = MinAlign(Alignment, 4U);
SDValue St1 = DAG.getStore(Chain, ST->getDebugLoc(), Hi,
Ptr, ST->getPointerInfo().getWithOffset(4),
isVolatile, isNonTemporal,
Alignment);
return DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), MVT::Other,
St0, St1);
}
break;
}
}
}
// Try to infer better alignment information than the store already has.
if (OptLevel != CodeGenOpt::None && ST->isUnindexed()) {
if (unsigned Align = DAG.InferPtrAlignment(Ptr)) {
if (Align > ST->getAlignment())
return DAG.getTruncStore(Chain, N->getDebugLoc(), Value,
Ptr, ST->getPointerInfo(), ST->getMemoryVT(),
ST->isVolatile(), ST->isNonTemporal(), Align);
}
}
// Try transforming a pair floating point load / store ops to integer
// load / store ops.
SDValue NewST = TransformFPLoadStorePair(N);
if (NewST.getNode())
return NewST;
if (CombinerAA) {
// Walk up chain skipping non-aliasing memory nodes.
SDValue BetterChain = FindBetterChain(N, Chain);
// If there is a better chain.
if (Chain != BetterChain) {
SDValue ReplStore;
// Replace the chain to avoid dependency.
if (ST->isTruncatingStore()) {
ReplStore = DAG.getTruncStore(BetterChain, N->getDebugLoc(), Value, Ptr,
ST->getPointerInfo(),
ST->getMemoryVT(), ST->isVolatile(),
ST->isNonTemporal(), ST->getAlignment());
} else {
ReplStore = DAG.getStore(BetterChain, N->getDebugLoc(), Value, Ptr,
ST->getPointerInfo(),
ST->isVolatile(), ST->isNonTemporal(),
ST->getAlignment());
}
// Create token to keep both nodes around.
SDValue Token = DAG.getNode(ISD::TokenFactor, N->getDebugLoc(),
MVT::Other, Chain, ReplStore);
// Make sure the new and old chains are cleaned up.
AddToWorkList(Token.getNode());
// Don't add users to work list.
return CombineTo(N, Token, false);
}
}
// Try transforming N to an indexed store.
if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N))
return SDValue(N, 0);
// FIXME: is there such a thing as a truncating indexed store?
if (ST->isTruncatingStore() && ST->isUnindexed() &&
Value.getValueType().isInteger()) {
// See if we can simplify the input to this truncstore with knowledge that
// only the low bits are being used. For example:
// "truncstore (or (shl x, 8), y), i8" -> "truncstore y, i8"
SDValue Shorter =
GetDemandedBits(Value,
APInt::getLowBitsSet(
Value.getValueType().getScalarType().getSizeInBits(),
ST->getMemoryVT().getScalarType().getSizeInBits()));
AddToWorkList(Value.getNode());
if (Shorter.getNode())
return DAG.getTruncStore(Chain, N->getDebugLoc(), Shorter,
Ptr, ST->getPointerInfo(), ST->getMemoryVT(),
ST->isVolatile(), ST->isNonTemporal(),
ST->getAlignment());
// Otherwise, see if we can simplify the operation with
// SimplifyDemandedBits, which only works if the value has a single use.
if (SimplifyDemandedBits(Value,
APInt::getLowBitsSet(
Value.getValueType().getScalarType().getSizeInBits(),
ST->getMemoryVT().getScalarType().getSizeInBits())))
return SDValue(N, 0);
}
// If this is a load followed by a store to the same location, then the store
// is dead/noop.
if (LoadSDNode *Ld = dyn_cast<LoadSDNode>(Value)) {
if (Ld->getBasePtr() == Ptr && ST->getMemoryVT() == Ld->getMemoryVT() &&
ST->isUnindexed() && !ST->isVolatile() &&
// There can't be any side effects between the load and store, such as
// a call or store.
Chain.reachesChainWithoutSideEffects(SDValue(Ld, 1))) {
// The store is dead, remove it.
return Chain;
}
}
// If this is an FP_ROUND or TRUNC followed by a store, fold this into a
// truncating store. We can do this even if this is already a truncstore.
if ((Value.getOpcode() == ISD::FP_ROUND || Value.getOpcode() == ISD::TRUNCATE)
&& Value.getNode()->hasOneUse() && ST->isUnindexed() &&
TLI.isTruncStoreLegal(Value.getOperand(0).getValueType(),
ST->getMemoryVT())) {
return DAG.getTruncStore(Chain, N->getDebugLoc(), Value.getOperand(0),
Ptr, ST->getPointerInfo(), ST->getMemoryVT(),
ST->isVolatile(), ST->isNonTemporal(),
ST->getAlignment());
}
return ReduceLoadOpStoreWidth(N);
}
SDValue DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) {
SDValue InVec = N->getOperand(0);
SDValue InVal = N->getOperand(1);
SDValue EltNo = N->getOperand(2);
// If the inserted element is an UNDEF, just use the input vector.
if (InVal.getOpcode() == ISD::UNDEF)
return InVec;
EVT VT = InVec.getValueType();
// If we can't generate a legal BUILD_VECTOR, exit
if (LegalOperations && !TLI.isOperationLegal(ISD::BUILD_VECTOR, VT))
return SDValue();
// If the invec is a BUILD_VECTOR and if EltNo is a constant, build a new
// vector with the inserted element.
if (InVec.getOpcode() == ISD::BUILD_VECTOR && isa<ConstantSDNode>(EltNo)) {
unsigned Elt = cast<ConstantSDNode>(EltNo)->getZExtValue();
SmallVector<SDValue, 8> Ops(InVec.getNode()->op_begin(),
InVec.getNode()->op_end());
if (Elt < Ops.size())
Ops[Elt] = InVal;
return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(),
VT, &Ops[0], Ops.size());
}
// If the invec is an UNDEF and if EltNo is a constant, create a new
// BUILD_VECTOR with undef elements and the inserted element.
if (InVec.getOpcode() == ISD::UNDEF &&
isa<ConstantSDNode>(EltNo)) {
EVT EltVT = VT.getVectorElementType();
unsigned NElts = VT.getVectorNumElements();
SmallVector<SDValue, 8> Ops(NElts, DAG.getUNDEF(EltVT));
unsigned Elt = cast<ConstantSDNode>(EltNo)->getZExtValue();
if (Elt < Ops.size())
Ops[Elt] = InVal;
return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(),
VT, &Ops[0], Ops.size());
}
return SDValue();
}
SDValue DAGCombiner::visitEXTRACT_VECTOR_ELT(SDNode *N) {
// (vextract (scalar_to_vector val, 0) -> val
SDValue InVec = N->getOperand(0);
if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR) {
// Check if the result type doesn't match the inserted element type. A
// SCALAR_TO_VECTOR may truncate the inserted element and the
// EXTRACT_VECTOR_ELT may widen the extracted vector.
SDValue InOp = InVec.getOperand(0);
EVT NVT = N->getValueType(0);
if (InOp.getValueType() != NVT) {
assert(InOp.getValueType().isInteger() && NVT.isInteger());
return DAG.getSExtOrTrunc(InOp, InVec.getDebugLoc(), NVT);
}
return InOp;
}
// Perform only after legalization to ensure build_vector / vector_shuffle
// optimizations have already been done.
if (!LegalOperations) return SDValue();
// (vextract (v4f32 load $addr), c) -> (f32 load $addr+c*size)
// (vextract (v4f32 s2v (f32 load $addr)), c) -> (f32 load $addr+c*size)
// (vextract (v4f32 shuffle (load $addr), <1,u,u,u>), 0) -> (f32 load $addr)
SDValue EltNo = N->getOperand(1);
if (isa<ConstantSDNode>(EltNo)) {
int Elt = cast<ConstantSDNode>(EltNo)->getZExtValue();
bool NewLoad = false;
bool BCNumEltsChanged = false;
EVT VT = InVec.getValueType();
EVT ExtVT = VT.getVectorElementType();
EVT LVT = ExtVT;
if (InVec.getOpcode() == ISD::BITCAST) {
EVT BCVT = InVec.getOperand(0).getValueType();
if (!BCVT.isVector() || ExtVT.bitsGT(BCVT.getVectorElementType()))
return SDValue();
if (VT.getVectorNumElements() != BCVT.getVectorNumElements())
BCNumEltsChanged = true;
InVec = InVec.getOperand(0);
ExtVT = BCVT.getVectorElementType();
NewLoad = true;
}
LoadSDNode *LN0 = NULL;
const ShuffleVectorSDNode *SVN = NULL;
if (ISD::isNormalLoad(InVec.getNode())) {
LN0 = cast<LoadSDNode>(InVec);
} else if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR &&
InVec.getOperand(0).getValueType() == ExtVT &&
ISD::isNormalLoad(InVec.getOperand(0).getNode())) {
LN0 = cast<LoadSDNode>(InVec.getOperand(0));
} else if ((SVN = dyn_cast<ShuffleVectorSDNode>(InVec))) {
// (vextract (vector_shuffle (load $addr), v2, <1, u, u, u>), 1)
// =>
// (load $addr+1*size)
// If the bit convert changed the number of elements, it is unsafe
// to examine the mask.
if (BCNumEltsChanged)
return SDValue();
// Select the input vector, guarding against out of range extract vector.
unsigned NumElems = VT.getVectorNumElements();
int Idx = (Elt > (int)NumElems) ? -1 : SVN->getMaskElt(Elt);
InVec = (Idx < (int)NumElems) ? InVec.getOperand(0) : InVec.getOperand(1);
if (InVec.getOpcode() == ISD::BITCAST)
InVec = InVec.getOperand(0);
if (ISD::isNormalLoad(InVec.getNode())) {
LN0 = cast<LoadSDNode>(InVec);
Elt = (Idx < (int)NumElems) ? Idx : Idx - (int)NumElems;
}
}
if (!LN0 || !LN0->hasNUsesOfValue(1,0) || LN0->isVolatile())
return SDValue();
// If Idx was -1 above, Elt is going to be -1, so just return undef.
if (Elt == -1)
return DAG.getUNDEF(LVT);
unsigned Align = LN0->getAlignment();
if (NewLoad) {
// Check the resultant load doesn't need a higher alignment than the
// original load.
unsigned NewAlign =
TLI.getTargetData()
->getABITypeAlignment(LVT.getTypeForEVT(*DAG.getContext()));
if (NewAlign > Align || !TLI.isOperationLegalOrCustom(ISD::LOAD, LVT))
return SDValue();
Align = NewAlign;
}
SDValue NewPtr = LN0->getBasePtr();
unsigned PtrOff = 0;
if (Elt) {
PtrOff = LVT.getSizeInBits() * Elt / 8;
EVT PtrType = NewPtr.getValueType();
if (TLI.isBigEndian())
PtrOff = VT.getSizeInBits() / 8 - PtrOff;
NewPtr = DAG.getNode(ISD::ADD, N->getDebugLoc(), PtrType, NewPtr,
DAG.getConstant(PtrOff, PtrType));
}
return DAG.getLoad(LVT, N->getDebugLoc(), LN0->getChain(), NewPtr,
LN0->getPointerInfo().getWithOffset(PtrOff),
LN0->isVolatile(), LN0->isNonTemporal(), Align);
}
return SDValue();
}
SDValue DAGCombiner::visitBUILD_VECTOR(SDNode *N) {
unsigned NumInScalars = N->getNumOperands();
EVT VT = N->getValueType(0);
// Check to see if this is a BUILD_VECTOR of a bunch of EXTRACT_VECTOR_ELT
// operations. If so, and if the EXTRACT_VECTOR_ELT vector inputs come from
// at most two distinct vectors, turn this into a shuffle node.
SDValue VecIn1, VecIn2;
for (unsigned i = 0; i != NumInScalars; ++i) {
// Ignore undef inputs.
if (N->getOperand(i).getOpcode() == ISD::UNDEF) continue;
// If this input is something other than a EXTRACT_VECTOR_ELT with a
// constant index, bail out.
if (N->getOperand(i).getOpcode() != ISD::EXTRACT_VECTOR_ELT ||
!isa<ConstantSDNode>(N->getOperand(i).getOperand(1))) {
VecIn1 = VecIn2 = SDValue(0, 0);
break;
}
// If the input vector type disagrees with the result of the build_vector,
// we can't make a shuffle.
SDValue ExtractedFromVec = N->getOperand(i).getOperand(0);
if (ExtractedFromVec.getValueType() != VT) {
VecIn1 = VecIn2 = SDValue(0, 0);
break;
}
// Otherwise, remember this. We allow up to two distinct input vectors.
if (ExtractedFromVec == VecIn1 || ExtractedFromVec == VecIn2)
continue;
if (VecIn1.getNode() == 0) {
VecIn1 = ExtractedFromVec;
} else if (VecIn2.getNode() == 0) {
VecIn2 = ExtractedFromVec;
} else {
// Too many inputs.
VecIn1 = VecIn2 = SDValue(0, 0);
break;
}
}
// If everything is good, we can make a shuffle operation.
if (VecIn1.getNode()) {
SmallVector<int, 8> Mask;
for (unsigned i = 0; i != NumInScalars; ++i) {
if (N->getOperand(i).getOpcode() == ISD::UNDEF) {
Mask.push_back(-1);
continue;
}
// If extracting from the first vector, just use the index directly.
SDValue Extract = N->getOperand(i);
SDValue ExtVal = Extract.getOperand(1);
if (Extract.getOperand(0) == VecIn1) {
unsigned ExtIndex = cast<ConstantSDNode>(ExtVal)->getZExtValue();
if (ExtIndex > VT.getVectorNumElements())
return SDValue();
Mask.push_back(ExtIndex);
continue;
}
// Otherwise, use InIdx + VecSize
unsigned Idx = cast<ConstantSDNode>(ExtVal)->getZExtValue();
Mask.push_back(Idx+NumInScalars);
}
// Add count and size info.
if (!isTypeLegal(VT))
return SDValue();
// Return the new VECTOR_SHUFFLE node.
SDValue Ops[2];
Ops[0] = VecIn1;
Ops[1] = VecIn2.getNode() ? VecIn2 : DAG.getUNDEF(VT);
return DAG.getVectorShuffle(VT, N->getDebugLoc(), Ops[0], Ops[1], &Mask[0]);
}
return SDValue();
}
SDValue DAGCombiner::visitCONCAT_VECTORS(SDNode *N) {
// TODO: Check to see if this is a CONCAT_VECTORS of a bunch of
// EXTRACT_SUBVECTOR operations. If so, and if the EXTRACT_SUBVECTOR vector
// inputs come from at most two distinct vectors, turn this into a shuffle
// node.
// If we only have one input vector, we don't need to do any concatenation.
if (N->getNumOperands() == 1)
return N->getOperand(0);
return SDValue();
}
SDValue DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) {
EVT VT = N->getValueType(0);
unsigned NumElts = VT.getVectorNumElements();
SDValue N0 = N->getOperand(0);
assert(N0.getValueType().getVectorNumElements() == NumElts &&
"Vector shuffle must be normalized in DAG");
// FIXME: implement canonicalizations from DAG.getVectorShuffle()
// If it is a splat, check if the argument vector is another splat or a
// build_vector with all scalar elements the same.
ShuffleVectorSDNode *SVN = cast<ShuffleVectorSDNode>(N);
if (SVN->isSplat() && SVN->getSplatIndex() < (int)NumElts) {
SDNode *V = N0.getNode();
// If this is a bit convert that changes the element type of the vector but
// not the number of vector elements, look through it. Be careful not to
// look though conversions that change things like v4f32 to v2f64.
if (V->getOpcode() == ISD::BITCAST) {
SDValue ConvInput = V->getOperand(0);
if (ConvInput.getValueType().isVector() &&
ConvInput.getValueType().getVectorNumElements() == NumElts)
V = ConvInput.getNode();
}
if (V->getOpcode() == ISD::BUILD_VECTOR) {
assert(V->getNumOperands() == NumElts &&
"BUILD_VECTOR has wrong number of operands");
SDValue Base;
bool AllSame = true;
for (unsigned i = 0; i != NumElts; ++i) {
if (V->getOperand(i).getOpcode() != ISD::UNDEF) {
Base = V->getOperand(i);
break;
}
}
// Splat of <u, u, u, u>, return <u, u, u, u>
if (!Base.getNode())
return N0;
for (unsigned i = 0; i != NumElts; ++i) {
if (V->getOperand(i) != Base) {
AllSame = false;
break;
}
}
// Splat of <x, x, x, x>, return <x, x, x, x>
if (AllSame)
return N0;
}
}
return SDValue();
}
SDValue DAGCombiner::visitMEMBARRIER(SDNode* N) {
if (!TLI.getShouldFoldAtomicFences())
return SDValue();
SDValue atomic = N->getOperand(0);
switch (atomic.getOpcode()) {
case ISD::ATOMIC_CMP_SWAP:
case ISD::ATOMIC_SWAP:
case ISD::ATOMIC_LOAD_ADD:
case ISD::ATOMIC_LOAD_SUB:
case ISD::ATOMIC_LOAD_AND:
case ISD::ATOMIC_LOAD_OR:
case ISD::ATOMIC_LOAD_XOR:
case ISD::ATOMIC_LOAD_NAND:
case ISD::ATOMIC_LOAD_MIN:
case ISD::ATOMIC_LOAD_MAX:
case ISD::ATOMIC_LOAD_UMIN:
case ISD::ATOMIC_LOAD_UMAX:
break;
default:
return SDValue();
}
SDValue fence = atomic.getOperand(0);
if (fence.getOpcode() != ISD::MEMBARRIER)
return SDValue();
switch (atomic.getOpcode()) {
case ISD::ATOMIC_CMP_SWAP:
return SDValue(DAG.UpdateNodeOperands(atomic.getNode(),
fence.getOperand(0),
atomic.getOperand(1), atomic.getOperand(2),
atomic.getOperand(3)), atomic.getResNo());
case ISD::ATOMIC_SWAP:
case ISD::ATOMIC_LOAD_ADD:
case ISD::ATOMIC_LOAD_SUB:
case ISD::ATOMIC_LOAD_AND:
case ISD::ATOMIC_LOAD_OR:
case ISD::ATOMIC_LOAD_XOR:
case ISD::ATOMIC_LOAD_NAND:
case ISD::ATOMIC_LOAD_MIN:
case ISD::ATOMIC_LOAD_MAX:
case ISD::ATOMIC_LOAD_UMIN:
case ISD::ATOMIC_LOAD_UMAX:
return SDValue(DAG.UpdateNodeOperands(atomic.getNode(),
fence.getOperand(0),
atomic.getOperand(1), atomic.getOperand(2)),
atomic.getResNo());
default:
return SDValue();
}
}
/// XformToShuffleWithZero - Returns a vector_shuffle if it able to transform
/// an AND to a vector_shuffle with the destination vector and a zero vector.
/// e.g. AND V, <0xffffffff, 0, 0xffffffff, 0>. ==>
/// vector_shuffle V, Zero, <0, 4, 2, 4>
SDValue DAGCombiner::XformToShuffleWithZero(SDNode *N) {
EVT VT = N->getValueType(0);
DebugLoc dl = N->getDebugLoc();
SDValue LHS = N->getOperand(0);
SDValue RHS = N->getOperand(1);
if (N->getOpcode() == ISD::AND) {
if (RHS.getOpcode() == ISD::BITCAST)
RHS = RHS.getOperand(0);
if (RHS.getOpcode() == ISD::BUILD_VECTOR) {
SmallVector<int, 8> Indices;
unsigned NumElts = RHS.getNumOperands();
for (unsigned i = 0; i != NumElts; ++i) {
SDValue Elt = RHS.getOperand(i);
if (!isa<ConstantSDNode>(Elt))
return SDValue();
else if (cast<ConstantSDNode>(Elt)->isAllOnesValue())
Indices.push_back(i);
else if (cast<ConstantSDNode>(Elt)->isNullValue())
Indices.push_back(NumElts);
else
return SDValue();
}
// Let's see if the target supports this vector_shuffle.
EVT RVT = RHS.getValueType();
if (!TLI.isVectorClearMaskLegal(Indices, RVT))
return SDValue();
// Return the new VECTOR_SHUFFLE node.
EVT EltVT = RVT.getVectorElementType();
SmallVector<SDValue,8> ZeroOps(RVT.getVectorNumElements(),
DAG.getConstant(0, EltVT));
SDValue Zero = DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(),
RVT, &ZeroOps[0], ZeroOps.size());
LHS = DAG.getNode(ISD::BITCAST, dl, RVT, LHS);
SDValue Shuf = DAG.getVectorShuffle(RVT, dl, LHS, Zero, &Indices[0]);
return DAG.getNode(ISD::BITCAST, dl, VT, Shuf);
}
}
return SDValue();
}
/// SimplifyVBinOp - Visit a binary vector operation, like ADD.
SDValue DAGCombiner::SimplifyVBinOp(SDNode *N) {
// After legalize, the target may be depending on adds and other
// binary ops to provide legal ways to construct constants or other
// things. Simplifying them may result in a loss of legality.
if (LegalOperations) return SDValue();
assert(N->getValueType(0).isVector() &&
"SimplifyVBinOp only works on vectors!");
SDValue LHS = N->getOperand(0);
SDValue RHS = N->getOperand(1);
SDValue Shuffle = XformToShuffleWithZero(N);
if (Shuffle.getNode()) return Shuffle;
// If the LHS and RHS are BUILD_VECTOR nodes, see if we can constant fold
// this operation.
if (LHS.getOpcode() == ISD::BUILD_VECTOR &&
RHS.getOpcode() == ISD::BUILD_VECTOR) {
SmallVector<SDValue, 8> Ops;
for (unsigned i = 0, e = LHS.getNumOperands(); i != e; ++i) {
SDValue LHSOp = LHS.getOperand(i);
SDValue RHSOp = RHS.getOperand(i);
// If these two elements can't be folded, bail out.
if ((LHSOp.getOpcode() != ISD::UNDEF &&
LHSOp.getOpcode() != ISD::Constant &&
LHSOp.getOpcode() != ISD::ConstantFP) ||
(RHSOp.getOpcode() != ISD::UNDEF &&
RHSOp.getOpcode() != ISD::Constant &&
RHSOp.getOpcode() != ISD::ConstantFP))
break;
// Can't fold divide by zero.
if (N->getOpcode() == ISD::SDIV || N->getOpcode() == ISD::UDIV ||
N->getOpcode() == ISD::FDIV) {
if ((RHSOp.getOpcode() == ISD::Constant &&
cast<ConstantSDNode>(RHSOp.getNode())->isNullValue()) ||
(RHSOp.getOpcode() == ISD::ConstantFP &&
cast<ConstantFPSDNode>(RHSOp.getNode())->getValueAPF().isZero()))
break;
}
EVT VT = LHSOp.getValueType();
assert(RHSOp.getValueType() == VT &&
"SimplifyVBinOp with different BUILD_VECTOR element types");
SDValue FoldOp = DAG.getNode(N->getOpcode(), LHS.getDebugLoc(), VT,
LHSOp, RHSOp);
if (FoldOp.getOpcode() != ISD::UNDEF &&
FoldOp.getOpcode() != ISD::Constant &&
FoldOp.getOpcode() != ISD::ConstantFP)
break;
Ops.push_back(FoldOp);
AddToWorkList(FoldOp.getNode());
}
if (Ops.size() == LHS.getNumOperands())
return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(),
LHS.getValueType(), &Ops[0], Ops.size());
}
return SDValue();
}
SDValue DAGCombiner::SimplifySelect(DebugLoc DL, SDValue N0,
SDValue N1, SDValue N2){
assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!");
SDValue SCC = SimplifySelectCC(DL, N0.getOperand(0), N0.getOperand(1), N1, N2,
cast<CondCodeSDNode>(N0.getOperand(2))->get());
// If we got a simplified select_cc node back from SimplifySelectCC, then
// break it down into a new SETCC node, and a new SELECT node, and then return
// the SELECT node, since we were called with a SELECT node.
if (SCC.getNode()) {
// Check to see if we got a select_cc back (to turn into setcc/select).
// Otherwise, just return whatever node we got back, like fabs.
if (SCC.getOpcode() == ISD::SELECT_CC) {
SDValue SETCC = DAG.getNode(ISD::SETCC, N0.getDebugLoc(),
N0.getValueType(),
SCC.getOperand(0), SCC.getOperand(1),
SCC.getOperand(4));
AddToWorkList(SETCC.getNode());
return DAG.getNode(ISD::SELECT, SCC.getDebugLoc(), SCC.getValueType(),
SCC.getOperand(2), SCC.getOperand(3), SETCC);
}
return SCC;
}
return SDValue();
}
/// SimplifySelectOps - Given a SELECT or a SELECT_CC node, where LHS and RHS
/// are the two values being selected between, see if we can simplify the
/// select. Callers of this should assume that TheSelect is deleted if this
/// returns true. As such, they should return the appropriate thing (e.g. the
/// node) back to the top-level of the DAG combiner loop to avoid it being
/// looked at.
bool DAGCombiner::SimplifySelectOps(SDNode *TheSelect, SDValue LHS,
SDValue RHS) {
// Cannot simplify select with vector condition
if (TheSelect->getOperand(0).getValueType().isVector()) return false;
// If this is a select from two identical things, try to pull the operation
// through the select.
if (LHS.getOpcode() != RHS.getOpcode() ||
!LHS.hasOneUse() || !RHS.hasOneUse())
return false;
// If this is a load and the token chain is identical, replace the select
// of two loads with a load through a select of the address to load from.
// This triggers in things like "select bool X, 10.0, 123.0" after the FP
// constants have been dropped into the constant pool.
if (LHS.getOpcode() == ISD::LOAD) {
LoadSDNode *LLD = cast<LoadSDNode>(LHS);
LoadSDNode *RLD = cast<LoadSDNode>(RHS);
// Token chains must be identical.
if (LHS.getOperand(0) != RHS.getOperand(0) ||
// Do not let this transformation reduce the number of volatile loads.
LLD->isVolatile() || RLD->isVolatile() ||
// If this is an EXTLOAD, the VT's must match.
LLD->getMemoryVT() != RLD->getMemoryVT() ||
// If this is an EXTLOAD, the kind of extension must match.
(LLD->getExtensionType() != RLD->getExtensionType() &&
// The only exception is if one of the extensions is anyext.
LLD->getExtensionType() != ISD::EXTLOAD &&
RLD->getExtensionType() != ISD::EXTLOAD) ||
// FIXME: this discards src value information. This is
// over-conservative. It would be beneficial to be able to remember
// both potential memory locations. Since we are discarding
// src value info, don't do the transformation if the memory
// locations are not in the default address space.
LLD->getPointerInfo().getAddrSpace() != 0 ||
RLD->getPointerInfo().getAddrSpace() != 0)
return false;
// Check that the select condition doesn't reach either load. If so,
// folding this will induce a cycle into the DAG. If not, this is safe to
// xform, so create a select of the addresses.
SDValue Addr;
if (TheSelect->getOpcode() == ISD::SELECT) {
SDNode *CondNode = TheSelect->getOperand(0).getNode();
if ((LLD->hasAnyUseOfValue(1) && LLD->isPredecessorOf(CondNode)) ||
(RLD->hasAnyUseOfValue(1) && RLD->isPredecessorOf(CondNode)))
return false;
Addr = DAG.getNode(ISD::SELECT, TheSelect->getDebugLoc(),
LLD->getBasePtr().getValueType(),
TheSelect->getOperand(0), LLD->getBasePtr(),
RLD->getBasePtr());
} else { // Otherwise SELECT_CC
SDNode *CondLHS = TheSelect->getOperand(0).getNode();
SDNode *CondRHS = TheSelect->getOperand(1).getNode();
if ((LLD->hasAnyUseOfValue(1) &&
(LLD->isPredecessorOf(CondLHS) || LLD->isPredecessorOf(CondRHS))) ||
(LLD->hasAnyUseOfValue(1) &&
(LLD->isPredecessorOf(CondLHS) || LLD->isPredecessorOf(CondRHS))))
return false;
Addr = DAG.getNode(ISD::SELECT_CC, TheSelect->getDebugLoc(),
LLD->getBasePtr().getValueType(),
TheSelect->getOperand(0),
TheSelect->getOperand(1),
LLD->getBasePtr(), RLD->getBasePtr(),
TheSelect->getOperand(4));
}
SDValue Load;
if (LLD->getExtensionType() == ISD::NON_EXTLOAD) {
Load = DAG.getLoad(TheSelect->getValueType(0),
TheSelect->getDebugLoc(),
// FIXME: Discards pointer info.
LLD->getChain(), Addr, MachinePointerInfo(),
LLD->isVolatile(), LLD->isNonTemporal(),
LLD->getAlignment());
} else {
Load = DAG.getExtLoad(LLD->getExtensionType() == ISD::EXTLOAD ?
RLD->getExtensionType() : LLD->getExtensionType(),
TheSelect->getDebugLoc(),
TheSelect->getValueType(0),
// FIXME: Discards pointer info.
LLD->getChain(), Addr, MachinePointerInfo(),
LLD->getMemoryVT(), LLD->isVolatile(),
LLD->isNonTemporal(), LLD->getAlignment());
}
// Users of the select now use the result of the load.
CombineTo(TheSelect, Load);
// Users of the old loads now use the new load's chain. We know the
// old-load value is dead now.
CombineTo(LHS.getNode(), Load.getValue(0), Load.getValue(1));
CombineTo(RHS.getNode(), Load.getValue(0), Load.getValue(1));
return true;
}
return false;
}
/// SimplifySelectCC - Simplify an expression of the form (N0 cond N1) ? N2 : N3
/// where 'cond' is the comparison specified by CC.
SDValue DAGCombiner::SimplifySelectCC(DebugLoc DL, SDValue N0, SDValue N1,
SDValue N2, SDValue N3,
ISD::CondCode CC, bool NotExtCompare) {
// (x ? y : y) -> y.
if (N2 == N3) return N2;
EVT VT = N2.getValueType();
ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode());
ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.getNode());
ConstantSDNode *N3C = dyn_cast<ConstantSDNode>(N3.getNode());
// Determine if the condition we're dealing with is constant
SDValue SCC = SimplifySetCC(TLI.getSetCCResultType(N0.getValueType()),
N0, N1, CC, DL, false);
if (SCC.getNode()) AddToWorkList(SCC.getNode());
ConstantSDNode *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.getNode());
// fold select_cc true, x, y -> x
if (SCCC && !SCCC->isNullValue())
return N2;
// fold select_cc false, x, y -> y
if (SCCC && SCCC->isNullValue())
return N3;
// Check to see if we can simplify the select into an fabs node
if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N1)) {
// Allow either -0.0 or 0.0
if (CFP->getValueAPF().isZero()) {
// select (setg[te] X, +/-0.0), X, fneg(X) -> fabs
if ((CC == ISD::SETGE || CC == ISD::SETGT) &&
N0 == N2 && N3.getOpcode() == ISD::FNEG &&
N2 == N3.getOperand(0))
return DAG.getNode(ISD::FABS, DL, VT, N0);
// select (setl[te] X, +/-0.0), fneg(X), X -> fabs
if ((CC == ISD::SETLT || CC == ISD::SETLE) &&
N0 == N3 && N2.getOpcode() == ISD::FNEG &&
N2.getOperand(0) == N3)
return DAG.getNode(ISD::FABS, DL, VT, N3);
}
}
// Turn "(a cond b) ? 1.0f : 2.0f" into "load (tmp + ((a cond b) ? 0 : 4)"
// where "tmp" is a constant pool entry containing an array with 1.0 and 2.0
// in it. This is a win when the constant is not otherwise available because
// it replaces two constant pool loads with one. We only do this if the FP
// type is known to be legal, because if it isn't, then we are before legalize
// types an we want the other legalization to happen first (e.g. to avoid
// messing with soft float) and if the ConstantFP is not legal, because if
// it is legal, we may not need to store the FP constant in a constant pool.
if (ConstantFPSDNode *TV = dyn_cast<ConstantFPSDNode>(N2))
if (ConstantFPSDNode *FV = dyn_cast<ConstantFPSDNode>(N3)) {
if (TLI.isTypeLegal(N2.getValueType()) &&
(TLI.getOperationAction(ISD::ConstantFP, N2.getValueType()) !=
TargetLowering::Legal) &&
// If both constants have multiple uses, then we won't need to do an
// extra load, they are likely around in registers for other users.
(TV->hasOneUse() || FV->hasOneUse())) {
Constant *Elts[] = {
const_cast<ConstantFP*>(FV->getConstantFPValue()),
const_cast<ConstantFP*>(TV->getConstantFPValue())
};
Type *FPTy = Elts[0]->getType();
const TargetData &TD = *TLI.getTargetData();
// Create a ConstantArray of the two constants.
Constant *CA = ConstantArray::get(ArrayType::get(FPTy, 2), Elts);
SDValue CPIdx = DAG.getConstantPool(CA, TLI.getPointerTy(),
TD.getPrefTypeAlignment(FPTy));
unsigned Alignment = cast<ConstantPoolSDNode>(CPIdx)->getAlignment();
// Get the offsets to the 0 and 1 element of the array so that we can
// select between them.
SDValue Zero = DAG.getIntPtrConstant(0);
unsigned EltSize = (unsigned)TD.getTypeAllocSize(Elts[0]->getType());
SDValue One = DAG.getIntPtrConstant(EltSize);
SDValue Cond = DAG.getSetCC(DL,
TLI.getSetCCResultType(N0.getValueType()),
N0, N1, CC);
SDValue CstOffset = DAG.getNode(ISD::SELECT, DL, Zero.getValueType(),
Cond, One, Zero);
CPIdx = DAG.getNode(ISD::ADD, DL, TLI.getPointerTy(), CPIdx,
CstOffset);
return DAG.getLoad(TV->getValueType(0), DL, DAG.getEntryNode(), CPIdx,
MachinePointerInfo::getConstantPool(), false,
false, Alignment);
}
}
// Check to see if we can perform the "gzip trick", transforming
// (select_cc setlt X, 0, A, 0) -> (and (sra X, (sub size(X), 1), A)
if (N1C && N3C && N3C->isNullValue() && CC == ISD::SETLT &&
N0.getValueType().isInteger() &&
N2.getValueType().isInteger() &&
(N1C->isNullValue() || // (a < 0) ? b : 0
(N1C->getAPIntValue() == 1 && N0 == N2))) { // (a < 1) ? a : 0
EVT XType = N0.getValueType();
EVT AType = N2.getValueType();
if (XType.bitsGE(AType)) {
// and (sra X, size(X)-1, A) -> "and (srl X, C2), A" iff A is a
// single-bit constant.
if (N2C && ((N2C->getAPIntValue() & (N2C->getAPIntValue()-1)) == 0)) {
unsigned ShCtV = N2C->getAPIntValue().logBase2();
ShCtV = XType.getSizeInBits()-ShCtV-1;
SDValue ShCt = DAG.getConstant(ShCtV,
getShiftAmountTy(N0.getValueType()));
SDValue Shift = DAG.getNode(ISD::SRL, N0.getDebugLoc(),
XType, N0, ShCt);
AddToWorkList(Shift.getNode());
if (XType.bitsGT(AType)) {
Shift = DAG.getNode(ISD::TRUNCATE, DL, AType, Shift);
AddToWorkList(Shift.getNode());
}
return DAG.getNode(ISD::AND, DL, AType, Shift, N2);
}
SDValue Shift = DAG.getNode(ISD::SRA, N0.getDebugLoc(),
XType, N0,
DAG.getConstant(XType.getSizeInBits()-1,
getShiftAmountTy(N0.getValueType())));
AddToWorkList(Shift.getNode());
if (XType.bitsGT(AType)) {
Shift = DAG.getNode(ISD::TRUNCATE, DL, AType, Shift);
AddToWorkList(Shift.getNode());
}
return DAG.getNode(ISD::AND, DL, AType, Shift, N2);
}
}
// fold (select_cc seteq (and x, y), 0, 0, A) -> (and (shr (shl x)) A)
// where y is has a single bit set.
// A plaintext description would be, we can turn the SELECT_CC into an AND
// when the condition can be materialized as an all-ones register. Any
// single bit-test can be materialized as an all-ones register with
// shift-left and shift-right-arith.
if (CC == ISD::SETEQ && N0->getOpcode() == ISD::AND &&
N0->getValueType(0) == VT &&
N1C && N1C->isNullValue() &&
N2C && N2C->isNullValue()) {
SDValue AndLHS = N0->getOperand(0);
ConstantSDNode *ConstAndRHS = dyn_cast<ConstantSDNode>(N0->getOperand(1));
if (ConstAndRHS && ConstAndRHS->getAPIntValue().countPopulation() == 1) {
// Shift the tested bit over the sign bit.
APInt AndMask = ConstAndRHS->getAPIntValue();
SDValue ShlAmt =
DAG.getConstant(AndMask.countLeadingZeros(),
getShiftAmountTy(AndLHS.getValueType()));
SDValue Shl = DAG.getNode(ISD::SHL, N0.getDebugLoc(), VT, AndLHS, ShlAmt);
// Now arithmetic right shift it all the way over, so the result is either
// all-ones, or zero.
SDValue ShrAmt =
DAG.getConstant(AndMask.getBitWidth()-1,
getShiftAmountTy(Shl.getValueType()));
SDValue Shr = DAG.getNode(ISD::SRA, N0.getDebugLoc(), VT, Shl, ShrAmt);
return DAG.getNode(ISD::AND, DL, VT, Shr, N3);
}
}
// fold select C, 16, 0 -> shl C, 4
if (N2C && N3C && N3C->isNullValue() && N2C->getAPIntValue().isPowerOf2() &&
TLI.getBooleanContents(N0.getValueType().isVector()) ==
TargetLowering::ZeroOrOneBooleanContent) {
// If the caller doesn't want us to simplify this into a zext of a compare,
// don't do it.
if (NotExtCompare && N2C->getAPIntValue() == 1)
return SDValue();
// Get a SetCC of the condition
// FIXME: Should probably make sure that setcc is legal if we ever have a
// target where it isn't.
SDValue Temp, SCC;
// cast from setcc result type to select result type
if (LegalTypes) {
SCC = DAG.getSetCC(DL, TLI.getSetCCResultType(N0.getValueType()),
N0, N1, CC);
if (N2.getValueType().bitsLT(SCC.getValueType()))
Temp = DAG.getZeroExtendInReg(SCC, N2.getDebugLoc(), N2.getValueType());
else
Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getDebugLoc(),
N2.getValueType(), SCC);
} else {
SCC = DAG.getSetCC(N0.getDebugLoc(), MVT::i1, N0, N1, CC);
Temp = DAG.getNode(ISD::ZERO_EXTEND, N2.getDebugLoc(),
N2.getValueType(), SCC);
}
AddToWorkList(SCC.getNode());
AddToWorkList(Temp.getNode());
if (N2C->getAPIntValue() == 1)
return Temp;
// shl setcc result by log2 n2c
return DAG.getNode(ISD::SHL, DL, N2.getValueType(), Temp,
DAG.getConstant(N2C->getAPIntValue().logBase2(),
getShiftAmountTy(Temp.getValueType())));
}
// Check to see if this is the equivalent of setcc
// FIXME: Turn all of these into setcc if setcc if setcc is legal
// otherwise, go ahead with the folds.
if (0 && N3C && N3C->isNullValue() && N2C && (N2C->getAPIntValue() == 1ULL)) {
EVT XType = N0.getValueType();
if (!LegalOperations ||
TLI.isOperationLegal(ISD::SETCC, TLI.getSetCCResultType(XType))) {
SDValue Res = DAG.getSetCC(DL, TLI.getSetCCResultType(XType), N0, N1, CC);
if (Res.getValueType() != VT)
Res = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, Res);
return Res;
}
// fold (seteq X, 0) -> (srl (ctlz X, log2(size(X))))
if (N1C && N1C->isNullValue() && CC == ISD::SETEQ &&
(!LegalOperations ||
TLI.isOperationLegal(ISD::CTLZ, XType))) {
SDValue Ctlz = DAG.getNode(ISD::CTLZ, N0.getDebugLoc(), XType, N0);
return DAG.getNode(ISD::SRL, DL, XType, Ctlz,
DAG.getConstant(Log2_32(XType.getSizeInBits()),
getShiftAmountTy(Ctlz.getValueType())));
}
// fold (setgt X, 0) -> (srl (and (-X, ~X), size(X)-1))
if (N1C && N1C->isNullValue() && CC == ISD::SETGT) {
SDValue NegN0 = DAG.getNode(ISD::SUB, N0.getDebugLoc(),
XType, DAG.getConstant(0, XType), N0);
SDValue NotN0 = DAG.getNOT(N0.getDebugLoc(), N0, XType);
return DAG.getNode(ISD::SRL, DL, XType,
DAG.getNode(ISD::AND, DL, XType, NegN0, NotN0),
DAG.getConstant(XType.getSizeInBits()-1,
getShiftAmountTy(XType)));
}
// fold (setgt X, -1) -> (xor (srl (X, size(X)-1), 1))
if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT) {
SDValue Sign = DAG.getNode(ISD::SRL, N0.getDebugLoc(), XType, N0,
DAG.getConstant(XType.getSizeInBits()-1,
getShiftAmountTy(N0.getValueType())));
return DAG.getNode(ISD::XOR, DL, XType, Sign, DAG.getConstant(1, XType));
}
}
// Check to see if this is an integer abs.
// select_cc setg[te] X, 0, X, -X ->
// select_cc setgt X, -1, X, -X ->
// select_cc setl[te] X, 0, -X, X ->
// select_cc setlt X, 1, -X, X ->
// Y = sra (X, size(X)-1); xor (add (X, Y), Y)
if (N1C) {
ConstantSDNode *SubC = NULL;
if (((N1C->isNullValue() && (CC == ISD::SETGT || CC == ISD::SETGE)) ||
(N1C->isAllOnesValue() && CC == ISD::SETGT)) &&
N0 == N2 && N3.getOpcode() == ISD::SUB && N0 == N3.getOperand(1))
SubC = dyn_cast<ConstantSDNode>(N3.getOperand(0));
else if (((N1C->isNullValue() && (CC == ISD::SETLT || CC == ISD::SETLE)) ||
(N1C->isOne() && CC == ISD::SETLT)) &&
N0 == N3 && N2.getOpcode() == ISD::SUB && N0 == N2.getOperand(1))
SubC = dyn_cast<ConstantSDNode>(N2.getOperand(0));
EVT XType = N0.getValueType();
if (SubC && SubC->isNullValue() && XType.isInteger()) {
SDValue Shift = DAG.getNode(ISD::SRA, N0.getDebugLoc(), XType,
N0,
DAG.getConstant(XType.getSizeInBits()-1,
getShiftAmountTy(N0.getValueType())));
SDValue Add = DAG.getNode(ISD::ADD, N0.getDebugLoc(),
XType, N0, Shift);
AddToWorkList(Shift.getNode());
AddToWorkList(Add.getNode());
return DAG.getNode(ISD::XOR, DL, XType, Add, Shift);
}
}
return SDValue();
}
/// SimplifySetCC - This is a stub for TargetLowering::SimplifySetCC.
SDValue DAGCombiner::SimplifySetCC(EVT VT, SDValue N0,
SDValue N1, ISD::CondCode Cond,
DebugLoc DL, bool foldBooleans) {
TargetLowering::DAGCombinerInfo
DagCombineInfo(DAG, !LegalTypes, !LegalOperations, false, this);
return TLI.SimplifySetCC(VT, N0, N1, Cond, foldBooleans, DagCombineInfo, DL);
}
/// BuildSDIVSequence - Given an ISD::SDIV node expressing a divide by constant,
/// return a DAG expression to select that will generate the same value by
/// multiplying by a magic number. See:
/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
SDValue DAGCombiner::BuildSDIV(SDNode *N) {
std::vector<SDNode*> Built;
SDValue S = TLI.BuildSDIV(N, DAG, &Built);
for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end();
ii != ee; ++ii)
AddToWorkList(*ii);
return S;
}
/// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant,
/// return a DAG expression to select that will generate the same value by
/// multiplying by a magic number. See:
/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
SDValue DAGCombiner::BuildUDIV(SDNode *N) {
std::vector<SDNode*> Built;
SDValue S = TLI.BuildUDIV(N, DAG, &Built);
for (std::vector<SDNode*>::iterator ii = Built.begin(), ee = Built.end();
ii != ee; ++ii)
AddToWorkList(*ii);
return S;
}
/// FindBaseOffset - Return true if base is a frame index, which is known not
// to alias with anything but itself. Provides base object and offset as
// results.
static bool FindBaseOffset(SDValue Ptr, SDValue &Base, int64_t &Offset,
const GlobalValue *&GV, void *&CV) {
// Assume it is a primitive operation.
Base = Ptr; Offset = 0; GV = 0; CV = 0;
// If it's an adding a simple constant then integrate the offset.
if (Base.getOpcode() == ISD::ADD) {
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Base.getOperand(1))) {
Base = Base.getOperand(0);
Offset += C->getZExtValue();
}
}
// Return the underlying GlobalValue, and update the Offset. Return false
// for GlobalAddressSDNode since the same GlobalAddress may be represented
// by multiple nodes with different offsets.
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Base)) {
GV = G->getGlobal();
Offset += G->getOffset();
return false;
}
// Return the underlying Constant value, and update the Offset. Return false
// for ConstantSDNodes since the same constant pool entry may be represented
// by multiple nodes with different offsets.
if (ConstantPoolSDNode *C = dyn_cast<ConstantPoolSDNode>(Base)) {
CV = C->isMachineConstantPoolEntry() ? (void *)C->getMachineCPVal()
: (void *)C->getConstVal();
Offset += C->getOffset();
return false;
}
// If it's any of the following then it can't alias with anything but itself.
return isa<FrameIndexSDNode>(Base);
}
/// isAlias - Return true if there is any possibility that the two addresses
/// overlap.
bool DAGCombiner::isAlias(SDValue Ptr1, int64_t Size1,
const Value *SrcValue1, int SrcValueOffset1,
unsigned SrcValueAlign1,
const MDNode *TBAAInfo1,
SDValue Ptr2, int64_t Size2,
const Value *SrcValue2, int SrcValueOffset2,
unsigned SrcValueAlign2,
const MDNode *TBAAInfo2) const {
// If they are the same then they must be aliases.
if (Ptr1 == Ptr2) return true;
// Gather base node and offset information.
SDValue Base1, Base2;
int64_t Offset1, Offset2;
const GlobalValue *GV1, *GV2;
void *CV1, *CV2;
bool isFrameIndex1 = FindBaseOffset(Ptr1, Base1, Offset1, GV1, CV1);
bool isFrameIndex2 = FindBaseOffset(Ptr2, Base2, Offset2, GV2, CV2);
// If they have a same base address then check to see if they overlap.
if (Base1 == Base2 || (GV1 && (GV1 == GV2)) || (CV1 && (CV1 == CV2)))
return !((Offset1 + Size1) <= Offset2 || (Offset2 + Size2) <= Offset1);
// It is possible for different frame indices to alias each other, mostly
// when tail call optimization reuses return address slots for arguments.
// To catch this case, look up the actual index of frame indices to compute
// the real alias relationship.
if (isFrameIndex1 && isFrameIndex2) {
MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo();
Offset1 += MFI->getObjectOffset(cast<FrameIndexSDNode>(Base1)->getIndex());
Offset2 += MFI->getObjectOffset(cast<FrameIndexSDNode>(Base2)->getIndex());
return !((Offset1 + Size1) <= Offset2 || (Offset2 + Size2) <= Offset1);
}
// Otherwise, if we know what the bases are, and they aren't identical, then
// we know they cannot alias.
if ((isFrameIndex1 || CV1 || GV1) && (isFrameIndex2 || CV2 || GV2))
return false;
// If we know required SrcValue1 and SrcValue2 have relatively large alignment
// compared to the size and offset of the access, we may be able to prove they
// do not alias. This check is conservative for now to catch cases created by
// splitting vector types.
if ((SrcValueAlign1 == SrcValueAlign2) &&
(SrcValueOffset1 != SrcValueOffset2) &&
(Size1 == Size2) && (SrcValueAlign1 > Size1)) {
int64_t OffAlign1 = SrcValueOffset1 % SrcValueAlign1;
int64_t OffAlign2 = SrcValueOffset2 % SrcValueAlign1;
// There is no overlap between these relatively aligned accesses of similar
// size, return no alias.
if ((OffAlign1 + Size1) <= OffAlign2 || (OffAlign2 + Size2) <= OffAlign1)
return false;
}
if (CombinerGlobalAA) {
// Use alias analysis information.
int64_t MinOffset = std::min(SrcValueOffset1, SrcValueOffset2);
int64_t Overlap1 = Size1 + SrcValueOffset1 - MinOffset;
int64_t Overlap2 = Size2 + SrcValueOffset2 - MinOffset;
AliasAnalysis::AliasResult AAResult =
AA.alias(AliasAnalysis::Location(SrcValue1, Overlap1, TBAAInfo1),
AliasAnalysis::Location(SrcValue2, Overlap2, TBAAInfo2));
if (AAResult == AliasAnalysis::NoAlias)
return false;
}
// Otherwise we have to assume they alias.
return true;
}
/// FindAliasInfo - Extracts the relevant alias information from the memory
/// node. Returns true if the operand was a load.
bool DAGCombiner::FindAliasInfo(SDNode *N,
SDValue &Ptr, int64_t &Size,
const Value *&SrcValue,
int &SrcValueOffset,
unsigned &SrcValueAlign,
const MDNode *&TBAAInfo) const {
if (LoadSDNode *LD = dyn_cast<LoadSDNode>(N)) {
Ptr = LD->getBasePtr();
Size = LD->getMemoryVT().getSizeInBits() >> 3;
SrcValue = LD->getSrcValue();
SrcValueOffset = LD->getSrcValueOffset();
SrcValueAlign = LD->getOriginalAlignment();
TBAAInfo = LD->getTBAAInfo();
return true;
}
if (StoreSDNode *ST = dyn_cast<StoreSDNode>(N)) {
Ptr = ST->getBasePtr();
Size = ST->getMemoryVT().getSizeInBits() >> 3;
SrcValue = ST->getSrcValue();
SrcValueOffset = ST->getSrcValueOffset();
SrcValueAlign = ST->getOriginalAlignment();
TBAAInfo = ST->getTBAAInfo();
return false;
}
llvm_unreachable("FindAliasInfo expected a memory operand");
}
/// GatherAllAliases - Walk up chain skipping non-aliasing memory nodes,
/// looking for aliasing nodes and adding them to the Aliases vector.
void DAGCombiner::GatherAllAliases(SDNode *N, SDValue OriginalChain,
SmallVector<SDValue, 8> &Aliases) {
SmallVector<SDValue, 8> Chains; // List of chains to visit.
SmallPtrSet<SDNode *, 16> Visited; // Visited node set.
// Get alias information for node.
SDValue Ptr;
int64_t Size;
const Value *SrcValue;
int SrcValueOffset;
unsigned SrcValueAlign;
const MDNode *SrcTBAAInfo;
bool IsLoad = FindAliasInfo(N, Ptr, Size, SrcValue, SrcValueOffset,
SrcValueAlign, SrcTBAAInfo);
// Starting off.
Chains.push_back(OriginalChain);
unsigned Depth = 0;
// Look at each chain and determine if it is an alias. If so, add it to the
// aliases list. If not, then continue up the chain looking for the next
// candidate.
while (!Chains.empty()) {
SDValue Chain = Chains.back();
Chains.pop_back();
// For TokenFactor nodes, look at each operand and only continue up the
// chain until we find two aliases. If we've seen two aliases, assume we'll
// find more and revert to original chain since the xform is unlikely to be
// profitable.
//
// FIXME: The depth check could be made to return the last non-aliasing
// chain we found before we hit a tokenfactor rather than the original
// chain.
if (Depth > 6 || Aliases.size() == 2) {
Aliases.clear();
Aliases.push_back(OriginalChain);
break;
}
// Don't bother if we've been before.
if (!Visited.insert(Chain.getNode()))
continue;
switch (Chain.getOpcode()) {
case ISD::EntryToken:
// Entry token is ideal chain operand, but handled in FindBetterChain.
break;
case ISD::LOAD:
case ISD::STORE: {
// Get alias information for Chain.
SDValue OpPtr;
int64_t OpSize;
const Value *OpSrcValue;
int OpSrcValueOffset;
unsigned OpSrcValueAlign;
const MDNode *OpSrcTBAAInfo;
bool IsOpLoad = FindAliasInfo(Chain.getNode(), OpPtr, OpSize,
OpSrcValue, OpSrcValueOffset,
OpSrcValueAlign,
OpSrcTBAAInfo);
// If chain is alias then stop here.
if (!(IsLoad && IsOpLoad) &&
isAlias(Ptr, Size, SrcValue, SrcValueOffset, SrcValueAlign,
SrcTBAAInfo,
OpPtr, OpSize, OpSrcValue, OpSrcValueOffset,
OpSrcValueAlign, OpSrcTBAAInfo)) {
Aliases.push_back(Chain);
} else {
// Look further up the chain.
Chains.push_back(Chain.getOperand(0));
++Depth;
}
break;
}
case ISD::TokenFactor:
// We have to check each of the operands of the token factor for "small"
// token factors, so we queue them up. Adding the operands to the queue
// (stack) in reverse order maintains the original order and increases the
// likelihood that getNode will find a matching token factor (CSE.)
if (Chain.getNumOperands() > 16) {
Aliases.push_back(Chain);
break;
}
for (unsigned n = Chain.getNumOperands(); n;)
Chains.push_back(Chain.getOperand(--n));
++Depth;
break;
default:
// For all other instructions we will just have to take what we can get.
Aliases.push_back(Chain);
break;
}
}
}
/// FindBetterChain - Walk up chain skipping non-aliasing memory nodes, looking
/// for a better chain (aliasing node.)
SDValue DAGCombiner::FindBetterChain(SDNode *N, SDValue OldChain) {
SmallVector<SDValue, 8> Aliases; // Ops for replacing token factor.
// Accumulate all the aliases to this node.
GatherAllAliases(N, OldChain, Aliases);
// If no operands then chain to entry token.
if (Aliases.size() == 0)
return DAG.getEntryNode();
// If a single operand then chain to it. We don't need to revisit it.
if (Aliases.size() == 1)
return Aliases[0];
// Construct a custom tailored token factor.
return DAG.getNode(ISD::TokenFactor, N->getDebugLoc(), MVT::Other,
&Aliases[0], Aliases.size());
}
// SelectionDAG::Combine - This is the entry point for the file.
//
void SelectionDAG::Combine(CombineLevel Level, AliasAnalysis &AA,
CodeGenOpt::Level OptLevel) {
/// run - This is the main entry point to this class.
///
DAGCombiner(*this, AA, OptLevel).Run(Level);
}
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