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llvm-6502/lib/Target/X86/X86ISelDAGToDAG.cpp
Chandler Carruth ab5a55e118 Cleanup and relax a restriction on the matching of global offsets into 
x86 addressing modes. This allows PIE-based TLS offsets to fit directly
into an addressing mode immediate offset, which is the last remaining
code quality issue from PR12380. With this patch, that PR is completely
fixed.

To understand why this patch is correct to match these offsets into
addressing mode immediates, break it down by cases:
1) 32-bit is trivially correct, and unmodified here.
2) 64-bit non-small mode is unchanged and never matches.
3) 64-bit small PIC code which is RIP-relative is handled specially in
   the match to try to fit RIP into the base register. If it fails, it
   now early exits. This behavior is unchanged by the patch.
4) 64-bit small non-PIC code which is not RIP-relative continues to work
   as it did before. The reason these immediates are safe is because the
   ABI ensures they fit in small mode. This behavior is unchanged.
5) 64-bit small PIC code which is *not* using RIP-relative addressing.
   This is the only case changed by the patch, and the primary place you
   see it is in TLS, either the win64 section offset TLS or Linux
   local-exec TLS model in a PIC compilation. Here the ABI again ensures
   that the immediates fit because we are in small mode, and any other
   operations required due to the PIC relocation model have been handled
   externally to the Wrapper node (extra loads etc are made around the
   wrapper node in ISelLowering).

I've tested this as much as I can comparing it with GCC's output, and
everything appears safe. I discussed this with Anton and it made sense
to him at least at face value. That said, if there are issues with PIC
code after this patch, yell and we can revert it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154304 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-09 02:13:06 +00:00

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//===- X86ISelDAGToDAG.cpp - A DAG pattern matching inst selector for X86 -===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines a DAG pattern matching instruction selector for X86,
// converting from a legalized dag to a X86 dag.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "x86-isel"
#include "X86.h"
#include "X86InstrBuilder.h"
#include "X86MachineFunctionInfo.h"
#include "X86RegisterInfo.h"
#include "X86Subtarget.h"
#include "X86TargetMachine.h"
#include "llvm/Instructions.h"
#include "llvm/Intrinsics.h"
#include "llvm/Type.h"
#include "llvm/CodeGen/FunctionLoweringInfo.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/Statistic.h"
using namespace llvm;
STATISTIC(NumLoadMoved, "Number of loads moved below TokenFactor");
//===----------------------------------------------------------------------===//
// Pattern Matcher Implementation
//===----------------------------------------------------------------------===//
namespace {
/// X86ISelAddressMode - This corresponds to X86AddressMode, but uses
/// SDValue's instead of register numbers for the leaves of the matched
/// tree.
struct X86ISelAddressMode {
enum {
RegBase,
FrameIndexBase
} BaseType;
// This is really a union, discriminated by BaseType!
SDValue Base_Reg;
int Base_FrameIndex;
unsigned Scale;
SDValue IndexReg;
int32_t Disp;
SDValue Segment;
const GlobalValue *GV;
const Constant *CP;
const BlockAddress *BlockAddr;
const char *ES;
int JT;
unsigned Align; // CP alignment.
unsigned char SymbolFlags; // X86II::MO_*
X86ISelAddressMode()
: BaseType(RegBase), Base_FrameIndex(0), Scale(1), IndexReg(), Disp(0),
Segment(), GV(0), CP(0), BlockAddr(0), ES(0), JT(-1), Align(0),
SymbolFlags(X86II::MO_NO_FLAG) {
}
bool hasSymbolicDisplacement() const {
return GV != 0 || CP != 0 || ES != 0 || JT != -1 || BlockAddr != 0;
}
bool hasBaseOrIndexReg() const {
return IndexReg.getNode() != 0 || Base_Reg.getNode() != 0;
}
/// isRIPRelative - Return true if this addressing mode is already RIP
/// relative.
bool isRIPRelative() const {
if (BaseType != RegBase) return false;
if (RegisterSDNode *RegNode =
dyn_cast_or_null<RegisterSDNode>(Base_Reg.getNode()))
return RegNode->getReg() == X86::RIP;
return false;
}
void setBaseReg(SDValue Reg) {
BaseType = RegBase;
Base_Reg = Reg;
}
void dump() {
dbgs() << "X86ISelAddressMode " << this << '\n';
dbgs() << "Base_Reg ";
if (Base_Reg.getNode() != 0)
Base_Reg.getNode()->dump();
else
dbgs() << "nul";
dbgs() << " Base.FrameIndex " << Base_FrameIndex << '\n'
<< " Scale" << Scale << '\n'
<< "IndexReg ";
if (IndexReg.getNode() != 0)
IndexReg.getNode()->dump();
else
dbgs() << "nul";
dbgs() << " Disp " << Disp << '\n'
<< "GV ";
if (GV)
GV->dump();
else
dbgs() << "nul";
dbgs() << " CP ";
if (CP)
CP->dump();
else
dbgs() << "nul";
dbgs() << '\n'
<< "ES ";
if (ES)
dbgs() << ES;
else
dbgs() << "nul";
dbgs() << " JT" << JT << " Align" << Align << '\n';
}
};
}
namespace {
//===--------------------------------------------------------------------===//
/// ISel - X86 specific code to select X86 machine instructions for
/// SelectionDAG operations.
///
class X86DAGToDAGISel : public SelectionDAGISel {
/// X86Lowering - This object fully describes how to lower LLVM code to an
/// X86-specific SelectionDAG.
const X86TargetLowering &X86Lowering;
/// Subtarget - Keep a pointer to the X86Subtarget around so that we can
/// make the right decision when generating code for different targets.
const X86Subtarget *Subtarget;
/// OptForSize - If true, selector should try to optimize for code size
/// instead of performance.
bool OptForSize;
public:
explicit X86DAGToDAGISel(X86TargetMachine &tm, CodeGenOpt::Level OptLevel)
: SelectionDAGISel(tm, OptLevel),
X86Lowering(*tm.getTargetLowering()),
Subtarget(&tm.getSubtarget<X86Subtarget>()),
OptForSize(false) {}
virtual const char *getPassName() const {
return "X86 DAG->DAG Instruction Selection";
}
virtual void EmitFunctionEntryCode();
virtual bool IsProfitableToFold(SDValue N, SDNode *U, SDNode *Root) const;
virtual void PreprocessISelDAG();
inline bool immSext8(SDNode *N) const {
return isInt<8>(cast<ConstantSDNode>(N)->getSExtValue());
}
// i64immSExt32 predicate - True if the 64-bit immediate fits in a 32-bit
// sign extended field.
inline bool i64immSExt32(SDNode *N) const {
uint64_t v = cast<ConstantSDNode>(N)->getZExtValue();
return (int64_t)v == (int32_t)v;
}
// Include the pieces autogenerated from the target description.
#include "X86GenDAGISel.inc"
private:
SDNode *Select(SDNode *N);
SDNode *SelectAtomic64(SDNode *Node, unsigned Opc);
SDNode *SelectAtomicLoadAdd(SDNode *Node, EVT NVT);
SDNode *SelectAtomicLoadArith(SDNode *Node, EVT NVT);
bool FoldOffsetIntoAddress(uint64_t Offset, X86ISelAddressMode &AM);
bool MatchLoadInAddress(LoadSDNode *N, X86ISelAddressMode &AM);
bool MatchWrapper(SDValue N, X86ISelAddressMode &AM);
bool MatchAddress(SDValue N, X86ISelAddressMode &AM);
bool MatchAddressRecursively(SDValue N, X86ISelAddressMode &AM,
unsigned Depth);
bool MatchAddressBase(SDValue N, X86ISelAddressMode &AM);
bool SelectAddr(SDNode *Parent, SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index, SDValue &Disp,
SDValue &Segment);
bool SelectLEAAddr(SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index, SDValue &Disp,
SDValue &Segment);
bool SelectTLSADDRAddr(SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index, SDValue &Disp,
SDValue &Segment);
bool SelectScalarSSELoad(SDNode *Root, SDValue N,
SDValue &Base, SDValue &Scale,
SDValue &Index, SDValue &Disp,
SDValue &Segment,
SDValue &NodeWithChain);
bool TryFoldLoad(SDNode *P, SDValue N,
SDValue &Base, SDValue &Scale,
SDValue &Index, SDValue &Disp,
SDValue &Segment);
/// SelectInlineAsmMemoryOperand - Implement addressing mode selection for
/// inline asm expressions.
virtual bool SelectInlineAsmMemoryOperand(const SDValue &Op,
char ConstraintCode,
std::vector<SDValue> &OutOps);
void EmitSpecialCodeForMain(MachineBasicBlock *BB, MachineFrameInfo *MFI);
inline void getAddressOperands(X86ISelAddressMode &AM, SDValue &Base,
SDValue &Scale, SDValue &Index,
SDValue &Disp, SDValue &Segment) {
Base = (AM.BaseType == X86ISelAddressMode::FrameIndexBase) ?
CurDAG->getTargetFrameIndex(AM.Base_FrameIndex, TLI.getPointerTy()) :
AM.Base_Reg;
Scale = getI8Imm(AM.Scale);
Index = AM.IndexReg;
// These are 32-bit even in 64-bit mode since RIP relative offset
// is 32-bit.
if (AM.GV)
Disp = CurDAG->getTargetGlobalAddress(AM.GV, DebugLoc(),
MVT::i32, AM.Disp,
AM.SymbolFlags);
else if (AM.CP)
Disp = CurDAG->getTargetConstantPool(AM.CP, MVT::i32,
AM.Align, AM.Disp, AM.SymbolFlags);
else if (AM.ES)
Disp = CurDAG->getTargetExternalSymbol(AM.ES, MVT::i32, AM.SymbolFlags);
else if (AM.JT != -1)
Disp = CurDAG->getTargetJumpTable(AM.JT, MVT::i32, AM.SymbolFlags);
else if (AM.BlockAddr)
Disp = CurDAG->getBlockAddress(AM.BlockAddr, MVT::i32,
true, AM.SymbolFlags);
else
Disp = CurDAG->getTargetConstant(AM.Disp, MVT::i32);
if (AM.Segment.getNode())
Segment = AM.Segment;
else
Segment = CurDAG->getRegister(0, MVT::i32);
}
/// getI8Imm - Return a target constant with the specified value, of type
/// i8.
inline SDValue getI8Imm(unsigned Imm) {
return CurDAG->getTargetConstant(Imm, MVT::i8);
}
/// getI32Imm - Return a target constant with the specified value, of type
/// i32.
inline SDValue getI32Imm(unsigned Imm) {
return CurDAG->getTargetConstant(Imm, MVT::i32);
}
/// getGlobalBaseReg - Return an SDNode that returns the value of
/// the global base register. Output instructions required to
/// initialize the global base register, if necessary.
///
SDNode *getGlobalBaseReg();
/// getTargetMachine - Return a reference to the TargetMachine, casted
/// to the target-specific type.
const X86TargetMachine &getTargetMachine() {
return static_cast<const X86TargetMachine &>(TM);
}
/// getInstrInfo - Return a reference to the TargetInstrInfo, casted
/// to the target-specific type.
const X86InstrInfo *getInstrInfo() {
return getTargetMachine().getInstrInfo();
}
};
}
bool
X86DAGToDAGISel::IsProfitableToFold(SDValue N, SDNode *U, SDNode *Root) const {
if (OptLevel == CodeGenOpt::None) return false;
if (!N.hasOneUse())
return false;
if (N.getOpcode() != ISD::LOAD)
return true;
// If N is a load, do additional profitability checks.
if (U == Root) {
switch (U->getOpcode()) {
default: break;
case X86ISD::ADD:
case X86ISD::SUB:
case X86ISD::AND:
case X86ISD::XOR:
case X86ISD::OR:
case ISD::ADD:
case ISD::ADDC:
case ISD::ADDE:
case ISD::AND:
case ISD::OR:
case ISD::XOR: {
SDValue Op1 = U->getOperand(1);
// If the other operand is a 8-bit immediate we should fold the immediate
// instead. This reduces code size.
// e.g.
// movl 4(%esp), %eax
// addl $4, %eax
// vs.
// movl $4, %eax
// addl 4(%esp), %eax
// The former is 2 bytes shorter. In case where the increment is 1, then
// the saving can be 4 bytes (by using incl %eax).
if (ConstantSDNode *Imm = dyn_cast<ConstantSDNode>(Op1))
if (Imm->getAPIntValue().isSignedIntN(8))
return false;
// If the other operand is a TLS address, we should fold it instead.
// This produces
// movl %gs:0, %eax
// leal i@NTPOFF(%eax), %eax
// instead of
// movl $i@NTPOFF, %eax
// addl %gs:0, %eax
// if the block also has an access to a second TLS address this will save
// a load.
// FIXME: This is probably also true for non TLS addresses.
if (Op1.getOpcode() == X86ISD::Wrapper) {
SDValue Val = Op1.getOperand(0);
if (Val.getOpcode() == ISD::TargetGlobalTLSAddress)
return false;
}
}
}
}
return true;
}
/// MoveBelowCallOrigChain - Replace the original chain operand of the call with
/// load's chain operand and move load below the call's chain operand.
static void MoveBelowOrigChain(SelectionDAG *CurDAG, SDValue Load,
SDValue Call, SDValue OrigChain) {
SmallVector<SDValue, 8> Ops;
SDValue Chain = OrigChain.getOperand(0);
if (Chain.getNode() == Load.getNode())
Ops.push_back(Load.getOperand(0));
else {
assert(Chain.getOpcode() == ISD::TokenFactor &&
"Unexpected chain operand");
for (unsigned i = 0, e = Chain.getNumOperands(); i != e; ++i)
if (Chain.getOperand(i).getNode() == Load.getNode())
Ops.push_back(Load.getOperand(0));
else
Ops.push_back(Chain.getOperand(i));
SDValue NewChain =
CurDAG->getNode(ISD::TokenFactor, Load.getDebugLoc(),
MVT::Other, &Ops[0], Ops.size());
Ops.clear();
Ops.push_back(NewChain);
}
for (unsigned i = 1, e = OrigChain.getNumOperands(); i != e; ++i)
Ops.push_back(OrigChain.getOperand(i));
CurDAG->UpdateNodeOperands(OrigChain.getNode(), &Ops[0], Ops.size());
CurDAG->UpdateNodeOperands(Load.getNode(), Call.getOperand(0),
Load.getOperand(1), Load.getOperand(2));
Ops.clear();
Ops.push_back(SDValue(Load.getNode(), 1));
for (unsigned i = 1, e = Call.getNode()->getNumOperands(); i != e; ++i)
Ops.push_back(Call.getOperand(i));
CurDAG->UpdateNodeOperands(Call.getNode(), &Ops[0], Ops.size());
}
/// isCalleeLoad - Return true if call address is a load and it can be
/// moved below CALLSEQ_START and the chains leading up to the call.
/// Return the CALLSEQ_START by reference as a second output.
/// In the case of a tail call, there isn't a callseq node between the call
/// chain and the load.
static bool isCalleeLoad(SDValue Callee, SDValue &Chain, bool HasCallSeq) {
if (Callee.getNode() == Chain.getNode() || !Callee.hasOneUse())
return false;
LoadSDNode *LD = dyn_cast<LoadSDNode>(Callee.getNode());
if (!LD ||
LD->isVolatile() ||
LD->getAddressingMode() != ISD::UNINDEXED ||
LD->getExtensionType() != ISD::NON_EXTLOAD)
return false;
// Now let's find the callseq_start.
while (HasCallSeq && Chain.getOpcode() != ISD::CALLSEQ_START) {
if (!Chain.hasOneUse())
return false;
Chain = Chain.getOperand(0);
}
if (!Chain.getNumOperands())
return false;
if (Chain.getOperand(0).getNode() == Callee.getNode())
return true;
if (Chain.getOperand(0).getOpcode() == ISD::TokenFactor &&
Callee.getValue(1).isOperandOf(Chain.getOperand(0).getNode()) &&
Callee.getValue(1).hasOneUse())
return true;
return false;
}
void X86DAGToDAGISel::PreprocessISelDAG() {
// OptForSize is used in pattern predicates that isel is matching.
OptForSize = MF->getFunction()->hasFnAttr(Attribute::OptimizeForSize);
for (SelectionDAG::allnodes_iterator I = CurDAG->allnodes_begin(),
E = CurDAG->allnodes_end(); I != E; ) {
SDNode *N = I++; // Preincrement iterator to avoid invalidation issues.
if (OptLevel != CodeGenOpt::None &&
(N->getOpcode() == X86ISD::CALL ||
N->getOpcode() == X86ISD::TC_RETURN)) {
/// Also try moving call address load from outside callseq_start to just
/// before the call to allow it to be folded.
///
/// [Load chain]
/// ^
/// |
/// [Load]
/// ^ ^
/// | |
/// / \--
/// / |
///[CALLSEQ_START] |
/// ^ |
/// | |
/// [LOAD/C2Reg] |
/// | |
/// \ /
/// \ /
/// [CALL]
bool HasCallSeq = N->getOpcode() == X86ISD::CALL;
SDValue Chain = N->getOperand(0);
SDValue Load = N->getOperand(1);
if (!isCalleeLoad(Load, Chain, HasCallSeq))
continue;
MoveBelowOrigChain(CurDAG, Load, SDValue(N, 0), Chain);
++NumLoadMoved;
continue;
}
// Lower fpround and fpextend nodes that target the FP stack to be store and
// load to the stack. This is a gross hack. We would like to simply mark
// these as being illegal, but when we do that, legalize produces these when
// it expands calls, then expands these in the same legalize pass. We would
// like dag combine to be able to hack on these between the call expansion
// and the node legalization. As such this pass basically does "really
// late" legalization of these inline with the X86 isel pass.
// FIXME: This should only happen when not compiled with -O0.
if (N->getOpcode() != ISD::FP_ROUND && N->getOpcode() != ISD::FP_EXTEND)
continue;
EVT SrcVT = N->getOperand(0).getValueType();
EVT DstVT = N->getValueType(0);
// If any of the sources are vectors, no fp stack involved.
if (SrcVT.isVector() || DstVT.isVector())
continue;
// If the source and destination are SSE registers, then this is a legal
// conversion that should not be lowered.
bool SrcIsSSE = X86Lowering.isScalarFPTypeInSSEReg(SrcVT);
bool DstIsSSE = X86Lowering.isScalarFPTypeInSSEReg(DstVT);
if (SrcIsSSE && DstIsSSE)
continue;
if (!SrcIsSSE && !DstIsSSE) {
// If this is an FPStack extension, it is a noop.
if (N->getOpcode() == ISD::FP_EXTEND)
continue;
// If this is a value-preserving FPStack truncation, it is a noop.
if (N->getConstantOperandVal(1))
continue;
}
// Here we could have an FP stack truncation or an FPStack <-> SSE convert.
// FPStack has extload and truncstore. SSE can fold direct loads into other
// operations. Based on this, decide what we want to do.
EVT MemVT;
if (N->getOpcode() == ISD::FP_ROUND)
MemVT = DstVT; // FP_ROUND must use DstVT, we can't do a 'trunc load'.
else
MemVT = SrcIsSSE ? SrcVT : DstVT;
SDValue MemTmp = CurDAG->CreateStackTemporary(MemVT);
DebugLoc dl = N->getDebugLoc();
// FIXME: optimize the case where the src/dest is a load or store?
SDValue Store = CurDAG->getTruncStore(CurDAG->getEntryNode(), dl,
N->getOperand(0),
MemTmp, MachinePointerInfo(), MemVT,
false, false, 0);
SDValue Result = CurDAG->getExtLoad(ISD::EXTLOAD, dl, DstVT, Store, MemTmp,
MachinePointerInfo(),
MemVT, false, false, 0);
// We're about to replace all uses of the FP_ROUND/FP_EXTEND with the
// extload we created. This will cause general havok on the dag because
// anything below the conversion could be folded into other existing nodes.
// To avoid invalidating 'I', back it up to the convert node.
--I;
CurDAG->ReplaceAllUsesOfValueWith(SDValue(N, 0), Result);
// Now that we did that, the node is dead. Increment the iterator to the
// next node to process, then delete N.
++I;
CurDAG->DeleteNode(N);
}
}
/// EmitSpecialCodeForMain - Emit any code that needs to be executed only in
/// the main function.
void X86DAGToDAGISel::EmitSpecialCodeForMain(MachineBasicBlock *BB,
MachineFrameInfo *MFI) {
const TargetInstrInfo *TII = TM.getInstrInfo();
if (Subtarget->isTargetCygMing()) {
unsigned CallOp =
Subtarget->is64Bit() ? X86::CALL64pcrel32 : X86::CALLpcrel32;
BuildMI(BB, DebugLoc(),
TII->get(CallOp)).addExternalSymbol("__main");
}
}
void X86DAGToDAGISel::EmitFunctionEntryCode() {
// If this is main, emit special code for main.
if (const Function *Fn = MF->getFunction())
if (Fn->hasExternalLinkage() && Fn->getName() == "main")
EmitSpecialCodeForMain(MF->begin(), MF->getFrameInfo());
}
static bool isDispSafeForFrameIndex(int64_t Val) {
// On 64-bit platforms, we can run into an issue where a frame index
// includes a displacement that, when added to the explicit displacement,
// will overflow the displacement field. Assuming that the frame index
// displacement fits into a 31-bit integer (which is only slightly more
// aggressive than the current fundamental assumption that it fits into
// a 32-bit integer), a 31-bit disp should always be safe.
return isInt<31>(Val);
}
bool X86DAGToDAGISel::FoldOffsetIntoAddress(uint64_t Offset,
X86ISelAddressMode &AM) {
int64_t Val = AM.Disp + Offset;
CodeModel::Model M = TM.getCodeModel();
if (Subtarget->is64Bit()) {
if (!X86::isOffsetSuitableForCodeModel(Val, M,
AM.hasSymbolicDisplacement()))
return true;
// In addition to the checks required for a register base, check that
// we do not try to use an unsafe Disp with a frame index.
if (AM.BaseType == X86ISelAddressMode::FrameIndexBase &&
!isDispSafeForFrameIndex(Val))
return true;
}
AM.Disp = Val;
return false;
}
bool X86DAGToDAGISel::MatchLoadInAddress(LoadSDNode *N, X86ISelAddressMode &AM){
SDValue Address = N->getOperand(1);
// load gs:0 -> GS segment register.
// load fs:0 -> FS segment register.
//
// This optimization is valid because the GNU TLS model defines that
// gs:0 (or fs:0 on X86-64) contains its own address.
// For more information see http://people.redhat.com/drepper/tls.pdf
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Address))
if (C->getSExtValue() == 0 && AM.Segment.getNode() == 0 &&
Subtarget->isTargetELF())
switch (N->getPointerInfo().getAddrSpace()) {
case 256:
AM.Segment = CurDAG->getRegister(X86::GS, MVT::i16);
return false;
case 257:
AM.Segment = CurDAG->getRegister(X86::FS, MVT::i16);
return false;
}
return true;
}
/// MatchWrapper - Try to match X86ISD::Wrapper and X86ISD::WrapperRIP nodes
/// into an addressing mode. These wrap things that will resolve down into a
/// symbol reference. If no match is possible, this returns true, otherwise it
/// returns false.
bool X86DAGToDAGISel::MatchWrapper(SDValue N, X86ISelAddressMode &AM) {
// If the addressing mode already has a symbol as the displacement, we can
// never match another symbol.
if (AM.hasSymbolicDisplacement())
return true;
SDValue N0 = N.getOperand(0);
CodeModel::Model M = TM.getCodeModel();
// Handle X86-64 rip-relative addresses. We check this before checking direct
// folding because RIP is preferable to non-RIP accesses.
if (Subtarget->is64Bit() && N.getOpcode() == X86ISD::WrapperRIP &&
// Under X86-64 non-small code model, GV (and friends) are 64-bits, so
// they cannot be folded into immediate fields.
// FIXME: This can be improved for kernel and other models?
(M == CodeModel::Small || M == CodeModel::Kernel)) {
// Base and index reg must be 0 in order to use %rip as base.
if (AM.hasBaseOrIndexReg())
return true;
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(N0)) {
X86ISelAddressMode Backup = AM;
AM.GV = G->getGlobal();
AM.SymbolFlags = G->getTargetFlags();
if (FoldOffsetIntoAddress(G->getOffset(), AM)) {
AM = Backup;
return true;
}
} else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(N0)) {
X86ISelAddressMode Backup = AM;
AM.CP = CP->getConstVal();
AM.Align = CP->getAlignment();
AM.SymbolFlags = CP->getTargetFlags();
if (FoldOffsetIntoAddress(CP->getOffset(), AM)) {
AM = Backup;
return true;
}
} else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(N0)) {
AM.ES = S->getSymbol();
AM.SymbolFlags = S->getTargetFlags();
} else if (JumpTableSDNode *J = dyn_cast<JumpTableSDNode>(N0)) {
AM.JT = J->getIndex();
AM.SymbolFlags = J->getTargetFlags();
} else {
AM.BlockAddr = cast<BlockAddressSDNode>(N0)->getBlockAddress();
AM.SymbolFlags = cast<BlockAddressSDNode>(N0)->getTargetFlags();
}
if (N.getOpcode() == X86ISD::WrapperRIP)
AM.setBaseReg(CurDAG->getRegister(X86::RIP, MVT::i64));
return false;
}
// Handle the case when globals fit in our immediate field: This is true for
// X86-32 always and X86-64 when in -mcmodel=small mode. In 64-bit
// mode, this only applies to a non-RIP-relative computation.
if (!Subtarget->is64Bit() ||
M == CodeModel::Small || M == CodeModel::Kernel) {
assert(N.getOpcode() != X86ISD::WrapperRIP &&
"RIP-relative addressing already handled");
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(N0)) {
AM.GV = G->getGlobal();
AM.Disp += G->getOffset();
AM.SymbolFlags = G->getTargetFlags();
} else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(N0)) {
AM.CP = CP->getConstVal();
AM.Align = CP->getAlignment();
AM.Disp += CP->getOffset();
AM.SymbolFlags = CP->getTargetFlags();
} else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(N0)) {
AM.ES = S->getSymbol();
AM.SymbolFlags = S->getTargetFlags();
} else if (JumpTableSDNode *J = dyn_cast<JumpTableSDNode>(N0)) {
AM.JT = J->getIndex();
AM.SymbolFlags = J->getTargetFlags();
} else {
AM.BlockAddr = cast<BlockAddressSDNode>(N0)->getBlockAddress();
AM.SymbolFlags = cast<BlockAddressSDNode>(N0)->getTargetFlags();
}
return false;
}
return true;
}
/// MatchAddress - Add the specified node to the specified addressing mode,
/// returning true if it cannot be done. This just pattern matches for the
/// addressing mode.
bool X86DAGToDAGISel::MatchAddress(SDValue N, X86ISelAddressMode &AM) {
if (MatchAddressRecursively(N, AM, 0))
return true;
// Post-processing: Convert lea(,%reg,2) to lea(%reg,%reg), which has
// a smaller encoding and avoids a scaled-index.
if (AM.Scale == 2 &&
AM.BaseType == X86ISelAddressMode::RegBase &&
AM.Base_Reg.getNode() == 0) {
AM.Base_Reg = AM.IndexReg;
AM.Scale = 1;
}
// Post-processing: Convert foo to foo(%rip), even in non-PIC mode,
// because it has a smaller encoding.
// TODO: Which other code models can use this?
if (TM.getCodeModel() == CodeModel::Small &&
Subtarget->is64Bit() &&
AM.Scale == 1 &&
AM.BaseType == X86ISelAddressMode::RegBase &&
AM.Base_Reg.getNode() == 0 &&
AM.IndexReg.getNode() == 0 &&
AM.SymbolFlags == X86II::MO_NO_FLAG &&
AM.hasSymbolicDisplacement())
AM.Base_Reg = CurDAG->getRegister(X86::RIP, MVT::i64);
return false;
}
// Insert a node into the DAG at least before the Pos node's position. This
// will reposition the node as needed, and will assign it a node ID that is <=
// the Pos node's ID. Note that this does *not* preserve the uniqueness of node
// IDs! The selection DAG must no longer depend on their uniqueness when this
// is used.
static void InsertDAGNode(SelectionDAG &DAG, SDValue Pos, SDValue N) {
if (N.getNode()->getNodeId() == -1 ||
N.getNode()->getNodeId() > Pos.getNode()->getNodeId()) {
DAG.RepositionNode(Pos.getNode(), N.getNode());
N.getNode()->setNodeId(Pos.getNode()->getNodeId());
}
}
// Transform "(X >> (8-C1)) & C2" to "(X >> 8) & 0xff)" if safe. This
// allows us to convert the shift and and into an h-register extract and
// a scaled index. Returns false if the simplification is performed.
static bool FoldMaskAndShiftToExtract(SelectionDAG &DAG, SDValue N,
uint64_t Mask,
SDValue Shift, SDValue X,
X86ISelAddressMode &AM) {
if (Shift.getOpcode() != ISD::SRL ||
!isa<ConstantSDNode>(Shift.getOperand(1)) ||
!Shift.hasOneUse())
return true;
int ScaleLog = 8 - Shift.getConstantOperandVal(1);
if (ScaleLog <= 0 || ScaleLog >= 4 ||
Mask != (0xffu << ScaleLog))
return true;
EVT VT = N.getValueType();
DebugLoc DL = N.getDebugLoc();
SDValue Eight = DAG.getConstant(8, MVT::i8);
SDValue NewMask = DAG.getConstant(0xff, VT);
SDValue Srl = DAG.getNode(ISD::SRL, DL, VT, X, Eight);
SDValue And = DAG.getNode(ISD::AND, DL, VT, Srl, NewMask);
SDValue ShlCount = DAG.getConstant(ScaleLog, MVT::i8);
SDValue Shl = DAG.getNode(ISD::SHL, DL, VT, And, ShlCount);
// Insert the new nodes into the topological ordering. We must do this in
// a valid topological ordering as nothing is going to go back and re-sort
// these nodes. We continually insert before 'N' in sequence as this is
// essentially a pre-flattened and pre-sorted sequence of nodes. There is no
// hierarchy left to express.
InsertDAGNode(DAG, N, Eight);
InsertDAGNode(DAG, N, Srl);
InsertDAGNode(DAG, N, NewMask);
InsertDAGNode(DAG, N, And);
InsertDAGNode(DAG, N, ShlCount);
InsertDAGNode(DAG, N, Shl);
DAG.ReplaceAllUsesWith(N, Shl);
AM.IndexReg = And;
AM.Scale = (1 << ScaleLog);
return false;
}
// Transforms "(X << C1) & C2" to "(X & (C2>>C1)) << C1" if safe and if this
// allows us to fold the shift into this addressing mode. Returns false if the
// transform succeeded.
static bool FoldMaskedShiftToScaledMask(SelectionDAG &DAG, SDValue N,
uint64_t Mask,
SDValue Shift, SDValue X,
X86ISelAddressMode &AM) {
if (Shift.getOpcode() != ISD::SHL ||
!isa<ConstantSDNode>(Shift.getOperand(1)))
return true;
// Not likely to be profitable if either the AND or SHIFT node has more
// than one use (unless all uses are for address computation). Besides,
// isel mechanism requires their node ids to be reused.
if (!N.hasOneUse() || !Shift.hasOneUse())
return true;
// Verify that the shift amount is something we can fold.
unsigned ShiftAmt = Shift.getConstantOperandVal(1);
if (ShiftAmt != 1 && ShiftAmt != 2 && ShiftAmt != 3)
return true;
EVT VT = N.getValueType();
DebugLoc DL = N.getDebugLoc();
SDValue NewMask = DAG.getConstant(Mask >> ShiftAmt, VT);
SDValue NewAnd = DAG.getNode(ISD::AND, DL, VT, X, NewMask);
SDValue NewShift = DAG.getNode(ISD::SHL, DL, VT, NewAnd, Shift.getOperand(1));
// Insert the new nodes into the topological ordering. We must do this in
// a valid topological ordering as nothing is going to go back and re-sort
// these nodes. We continually insert before 'N' in sequence as this is
// essentially a pre-flattened and pre-sorted sequence of nodes. There is no
// hierarchy left to express.
InsertDAGNode(DAG, N, NewMask);
InsertDAGNode(DAG, N, NewAnd);
InsertDAGNode(DAG, N, NewShift);
DAG.ReplaceAllUsesWith(N, NewShift);
AM.Scale = 1 << ShiftAmt;
AM.IndexReg = NewAnd;
return false;
}
// Implement some heroics to detect shifts of masked values where the mask can
// be replaced by extending the shift and undoing that in the addressing mode
// scale. Patterns such as (shl (srl x, c1), c2) are canonicalized into (and
// (srl x, SHIFT), MASK) by DAGCombines that don't know the shl can be done in
// the addressing mode. This results in code such as:
//
// int f(short *y, int *lookup_table) {
// ...
// return *y + lookup_table[*y >> 11];
// }
//
// Turning into:
// movzwl (%rdi), %eax
// movl %eax, %ecx
// shrl $11, %ecx
// addl (%rsi,%rcx,4), %eax
//
// Instead of:
// movzwl (%rdi), %eax
// movl %eax, %ecx
// shrl $9, %ecx
// andl $124, %rcx
// addl (%rsi,%rcx), %eax
//
// Note that this function assumes the mask is provided as a mask *after* the
// value is shifted. The input chain may or may not match that, but computing
// such a mask is trivial.
static bool FoldMaskAndShiftToScale(SelectionDAG &DAG, SDValue N,
uint64_t Mask,
SDValue Shift, SDValue X,
X86ISelAddressMode &AM) {
if (Shift.getOpcode() != ISD::SRL || !Shift.hasOneUse() ||
!isa<ConstantSDNode>(Shift.getOperand(1)))
return true;
unsigned ShiftAmt = Shift.getConstantOperandVal(1);
unsigned MaskLZ = CountLeadingZeros_64(Mask);
unsigned MaskTZ = CountTrailingZeros_64(Mask);
// The amount of shift we're trying to fit into the addressing mode is taken
// from the trailing zeros of the mask.
unsigned AMShiftAmt = MaskTZ;
// There is nothing we can do here unless the mask is removing some bits.
// Also, the addressing mode can only represent shifts of 1, 2, or 3 bits.
if (AMShiftAmt <= 0 || AMShiftAmt > 3) return true;
// We also need to ensure that mask is a continuous run of bits.
if (CountTrailingOnes_64(Mask >> MaskTZ) + MaskTZ + MaskLZ != 64) return true;
// Scale the leading zero count down based on the actual size of the value.
// Also scale it down based on the size of the shift.
MaskLZ -= (64 - X.getValueSizeInBits()) + ShiftAmt;
// The final check is to ensure that any masked out high bits of X are
// already known to be zero. Otherwise, the mask has a semantic impact
// other than masking out a couple of low bits. Unfortunately, because of
// the mask, zero extensions will be removed from operands in some cases.
// This code works extra hard to look through extensions because we can
// replace them with zero extensions cheaply if necessary.
bool ReplacingAnyExtend = false;
if (X.getOpcode() == ISD::ANY_EXTEND) {
unsigned ExtendBits =
X.getValueSizeInBits() - X.getOperand(0).getValueSizeInBits();
// Assume that we'll replace the any-extend with a zero-extend, and
// narrow the search to the extended value.
X = X.getOperand(0);
MaskLZ = ExtendBits > MaskLZ ? 0 : MaskLZ - ExtendBits;
ReplacingAnyExtend = true;
}
APInt MaskedHighBits = APInt::getHighBitsSet(X.getValueSizeInBits(),
MaskLZ);
APInt KnownZero, KnownOne;
DAG.ComputeMaskedBits(X, KnownZero, KnownOne);
if (MaskedHighBits != KnownZero) return true;
// We've identified a pattern that can be transformed into a single shift
// and an addressing mode. Make it so.
EVT VT = N.getValueType();
if (ReplacingAnyExtend) {
assert(X.getValueType() != VT);
// We looked through an ANY_EXTEND node, insert a ZERO_EXTEND.
SDValue NewX = DAG.getNode(ISD::ZERO_EXTEND, X.getDebugLoc(), VT, X);
InsertDAGNode(DAG, N, NewX);
X = NewX;
}
DebugLoc DL = N.getDebugLoc();
SDValue NewSRLAmt = DAG.getConstant(ShiftAmt + AMShiftAmt, MVT::i8);
SDValue NewSRL = DAG.getNode(ISD::SRL, DL, VT, X, NewSRLAmt);
SDValue NewSHLAmt = DAG.getConstant(AMShiftAmt, MVT::i8);
SDValue NewSHL = DAG.getNode(ISD::SHL, DL, VT, NewSRL, NewSHLAmt);
// Insert the new nodes into the topological ordering. We must do this in
// a valid topological ordering as nothing is going to go back and re-sort
// these nodes. We continually insert before 'N' in sequence as this is
// essentially a pre-flattened and pre-sorted sequence of nodes. There is no
// hierarchy left to express.
InsertDAGNode(DAG, N, NewSRLAmt);
InsertDAGNode(DAG, N, NewSRL);
InsertDAGNode(DAG, N, NewSHLAmt);
InsertDAGNode(DAG, N, NewSHL);
DAG.ReplaceAllUsesWith(N, NewSHL);
AM.Scale = 1 << AMShiftAmt;
AM.IndexReg = NewSRL;
return false;
}
bool X86DAGToDAGISel::MatchAddressRecursively(SDValue N, X86ISelAddressMode &AM,
unsigned Depth) {
DebugLoc dl = N.getDebugLoc();
DEBUG({
dbgs() << "MatchAddress: ";
AM.dump();
});
// Limit recursion.
if (Depth > 5)
return MatchAddressBase(N, AM);
// If this is already a %rip relative address, we can only merge immediates
// into it. Instead of handling this in every case, we handle it here.
// RIP relative addressing: %rip + 32-bit displacement!
if (AM.isRIPRelative()) {
// FIXME: JumpTable and ExternalSymbol address currently don't like
// displacements. It isn't very important, but this should be fixed for
// consistency.
if (!AM.ES && AM.JT != -1) return true;
if (ConstantSDNode *Cst = dyn_cast<ConstantSDNode>(N))
if (!FoldOffsetIntoAddress(Cst->getSExtValue(), AM))
return false;
return true;
}
switch (N.getOpcode()) {
default: break;
case ISD::Constant: {
uint64_t Val = cast<ConstantSDNode>(N)->getSExtValue();
if (!FoldOffsetIntoAddress(Val, AM))
return false;
break;
}
case X86ISD::Wrapper:
case X86ISD::WrapperRIP:
if (!MatchWrapper(N, AM))
return false;
break;
case ISD::LOAD:
if (!MatchLoadInAddress(cast<LoadSDNode>(N), AM))
return false;
break;
case ISD::FrameIndex:
if (AM.BaseType == X86ISelAddressMode::RegBase &&
AM.Base_Reg.getNode() == 0 &&
(!Subtarget->is64Bit() || isDispSafeForFrameIndex(AM.Disp))) {
AM.BaseType = X86ISelAddressMode::FrameIndexBase;
AM.Base_FrameIndex = cast<FrameIndexSDNode>(N)->getIndex();
return false;
}
break;
case ISD::SHL:
if (AM.IndexReg.getNode() != 0 || AM.Scale != 1)
break;
if (ConstantSDNode
*CN = dyn_cast<ConstantSDNode>(N.getNode()->getOperand(1))) {
unsigned Val = CN->getZExtValue();
// Note that we handle x<<1 as (,x,2) rather than (x,x) here so
// that the base operand remains free for further matching. If
// the base doesn't end up getting used, a post-processing step
// in MatchAddress turns (,x,2) into (x,x), which is cheaper.
if (Val == 1 || Val == 2 || Val == 3) {
AM.Scale = 1 << Val;
SDValue ShVal = N.getNode()->getOperand(0);
// Okay, we know that we have a scale by now. However, if the scaled
// value is an add of something and a constant, we can fold the
// constant into the disp field here.
if (CurDAG->isBaseWithConstantOffset(ShVal)) {
AM.IndexReg = ShVal.getNode()->getOperand(0);
ConstantSDNode *AddVal =
cast<ConstantSDNode>(ShVal.getNode()->getOperand(1));
uint64_t Disp = AddVal->getSExtValue() << Val;
if (!FoldOffsetIntoAddress(Disp, AM))
return false;
}
AM.IndexReg = ShVal;
return false;
}
break;
}
case ISD::SRL: {
// Scale must not be used already.
if (AM.IndexReg.getNode() != 0 || AM.Scale != 1) break;
SDValue And = N.getOperand(0);
if (And.getOpcode() != ISD::AND) break;
SDValue X = And.getOperand(0);
// We only handle up to 64-bit values here as those are what matter for
// addressing mode optimizations.
if (X.getValueSizeInBits() > 64) break;
// The mask used for the transform is expected to be post-shift, but we
// found the shift first so just apply the shift to the mask before passing
// it down.
if (!isa<ConstantSDNode>(N.getOperand(1)) ||
!isa<ConstantSDNode>(And.getOperand(1)))
break;
uint64_t Mask = And.getConstantOperandVal(1) >> N.getConstantOperandVal(1);
// Try to fold the mask and shift into the scale, and return false if we
// succeed.
if (!FoldMaskAndShiftToScale(*CurDAG, N, Mask, N, X, AM))
return false;
break;
}
case ISD::SMUL_LOHI:
case ISD::UMUL_LOHI:
// A mul_lohi where we need the low part can be folded as a plain multiply.
if (N.getResNo() != 0) break;
// FALL THROUGH
case ISD::MUL:
case X86ISD::MUL_IMM:
// X*[3,5,9] -> X+X*[2,4,8]
if (AM.BaseType == X86ISelAddressMode::RegBase &&
AM.Base_Reg.getNode() == 0 &&
AM.IndexReg.getNode() == 0) {
if (ConstantSDNode
*CN = dyn_cast<ConstantSDNode>(N.getNode()->getOperand(1)))
if (CN->getZExtValue() == 3 || CN->getZExtValue() == 5 ||
CN->getZExtValue() == 9) {
AM.Scale = unsigned(CN->getZExtValue())-1;
SDValue MulVal = N.getNode()->getOperand(0);
SDValue Reg;
// Okay, we know that we have a scale by now. However, if the scaled
// value is an add of something and a constant, we can fold the
// constant into the disp field here.
if (MulVal.getNode()->getOpcode() == ISD::ADD && MulVal.hasOneUse() &&
isa<ConstantSDNode>(MulVal.getNode()->getOperand(1))) {
Reg = MulVal.getNode()->getOperand(0);
ConstantSDNode *AddVal =
cast<ConstantSDNode>(MulVal.getNode()->getOperand(1));
uint64_t Disp = AddVal->getSExtValue() * CN->getZExtValue();
if (FoldOffsetIntoAddress(Disp, AM))
Reg = N.getNode()->getOperand(0);
} else {
Reg = N.getNode()->getOperand(0);
}
AM.IndexReg = AM.Base_Reg = Reg;
return false;
}
}
break;
case ISD::SUB: {
// Given A-B, if A can be completely folded into the address and
// the index field with the index field unused, use -B as the index.
// This is a win if a has multiple parts that can be folded into
// the address. Also, this saves a mov if the base register has
// other uses, since it avoids a two-address sub instruction, however
// it costs an additional mov if the index register has other uses.
// Add an artificial use to this node so that we can keep track of
// it if it gets CSE'd with a different node.
HandleSDNode Handle(N);
// Test if the LHS of the sub can be folded.
X86ISelAddressMode Backup = AM;
if (MatchAddressRecursively(N.getNode()->getOperand(0), AM, Depth+1)) {
AM = Backup;
break;
}
// Test if the index field is free for use.
if (AM.IndexReg.getNode() || AM.isRIPRelative()) {
AM = Backup;
break;
}
int Cost = 0;
SDValue RHS = Handle.getValue().getNode()->getOperand(1);
// If the RHS involves a register with multiple uses, this
// transformation incurs an extra mov, due to the neg instruction
// clobbering its operand.
if (!RHS.getNode()->hasOneUse() ||
RHS.getNode()->getOpcode() == ISD::CopyFromReg ||
RHS.getNode()->getOpcode() == ISD::TRUNCATE ||
RHS.getNode()->getOpcode() == ISD::ANY_EXTEND ||
(RHS.getNode()->getOpcode() == ISD::ZERO_EXTEND &&
RHS.getNode()->getOperand(0).getValueType() == MVT::i32))
++Cost;
// If the base is a register with multiple uses, this
// transformation may save a mov.
if ((AM.BaseType == X86ISelAddressMode::RegBase &&
AM.Base_Reg.getNode() &&
!AM.Base_Reg.getNode()->hasOneUse()) ||
AM.BaseType == X86ISelAddressMode::FrameIndexBase)
--Cost;
// If the folded LHS was interesting, this transformation saves
// address arithmetic.
if ((AM.hasSymbolicDisplacement() && !Backup.hasSymbolicDisplacement()) +
((AM.Disp != 0) && (Backup.Disp == 0)) +
(AM.Segment.getNode() && !Backup.Segment.getNode()) >= 2)
--Cost;
// If it doesn't look like it may be an overall win, don't do it.
if (Cost >= 0) {
AM = Backup;
break;
}
// Ok, the transformation is legal and appears profitable. Go for it.
SDValue Zero = CurDAG->getConstant(0, N.getValueType());
SDValue Neg = CurDAG->getNode(ISD::SUB, dl, N.getValueType(), Zero, RHS);
AM.IndexReg = Neg;
AM.Scale = 1;
// Insert the new nodes into the topological ordering.
InsertDAGNode(*CurDAG, N, Zero);
InsertDAGNode(*CurDAG, N, Neg);
return false;
}
case ISD::ADD: {
// Add an artificial use to this node so that we can keep track of
// it if it gets CSE'd with a different node.
HandleSDNode Handle(N);
X86ISelAddressMode Backup = AM;
if (!MatchAddressRecursively(N.getOperand(0), AM, Depth+1) &&
!MatchAddressRecursively(Handle.getValue().getOperand(1), AM, Depth+1))
return false;
AM = Backup;
// Try again after commuting the operands.
if (!MatchAddressRecursively(Handle.getValue().getOperand(1), AM, Depth+1)&&
!MatchAddressRecursively(Handle.getValue().getOperand(0), AM, Depth+1))
return false;
AM = Backup;
// If we couldn't fold both operands into the address at the same time,
// see if we can just put each operand into a register and fold at least
// the add.
if (AM.BaseType == X86ISelAddressMode::RegBase &&
!AM.Base_Reg.getNode() &&
!AM.IndexReg.getNode()) {
N = Handle.getValue();
AM.Base_Reg = N.getOperand(0);
AM.IndexReg = N.getOperand(1);
AM.Scale = 1;
return false;
}
N = Handle.getValue();
break;
}
case ISD::OR:
// Handle "X | C" as "X + C" iff X is known to have C bits clear.
if (CurDAG->isBaseWithConstantOffset(N)) {
X86ISelAddressMode Backup = AM;
ConstantSDNode *CN = cast<ConstantSDNode>(N.getOperand(1));
// Start with the LHS as an addr mode.
if (!MatchAddressRecursively(N.getOperand(0), AM, Depth+1) &&
!FoldOffsetIntoAddress(CN->getSExtValue(), AM))
return false;
AM = Backup;
}
break;
case ISD::AND: {
// Perform some heroic transforms on an and of a constant-count shift
// with a constant to enable use of the scaled offset field.
// Scale must not be used already.
if (AM.IndexReg.getNode() != 0 || AM.Scale != 1) break;
SDValue Shift = N.getOperand(0);
if (Shift.getOpcode() != ISD::SRL && Shift.getOpcode() != ISD::SHL) break;
SDValue X = Shift.getOperand(0);
// We only handle up to 64-bit values here as those are what matter for
// addressing mode optimizations.
if (X.getValueSizeInBits() > 64) break;
if (!isa<ConstantSDNode>(N.getOperand(1)))
break;
uint64_t Mask = N.getConstantOperandVal(1);
// Try to fold the mask and shift into an extract and scale.
if (!FoldMaskAndShiftToExtract(*CurDAG, N, Mask, Shift, X, AM))
return false;
// Try to fold the mask and shift directly into the scale.
if (!FoldMaskAndShiftToScale(*CurDAG, N, Mask, Shift, X, AM))
return false;
// Try to swap the mask and shift to place shifts which can be done as
// a scale on the outside of the mask.
if (!FoldMaskedShiftToScaledMask(*CurDAG, N, Mask, Shift, X, AM))
return false;
break;
}
}
return MatchAddressBase(N, AM);
}
/// MatchAddressBase - Helper for MatchAddress. Add the specified node to the
/// specified addressing mode without any further recursion.
bool X86DAGToDAGISel::MatchAddressBase(SDValue N, X86ISelAddressMode &AM) {
// Is the base register already occupied?
if (AM.BaseType != X86ISelAddressMode::RegBase || AM.Base_Reg.getNode()) {
// If so, check to see if the scale index register is set.
if (AM.IndexReg.getNode() == 0) {
AM.IndexReg = N;
AM.Scale = 1;
return false;
}
// Otherwise, we cannot select it.
return true;
}
// Default, generate it as a register.
AM.BaseType = X86ISelAddressMode::RegBase;
AM.Base_Reg = N;
return false;
}
/// SelectAddr - returns true if it is able pattern match an addressing mode.
/// It returns the operands which make up the maximal addressing mode it can
/// match by reference.
///
/// Parent is the parent node of the addr operand that is being matched. It
/// is always a load, store, atomic node, or null. It is only null when
/// checking memory operands for inline asm nodes.
bool X86DAGToDAGISel::SelectAddr(SDNode *Parent, SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index,
SDValue &Disp, SDValue &Segment) {
X86ISelAddressMode AM;
if (Parent &&
// This list of opcodes are all the nodes that have an "addr:$ptr" operand
// that are not a MemSDNode, and thus don't have proper addrspace info.
Parent->getOpcode() != ISD::INTRINSIC_W_CHAIN && // unaligned loads, fixme
Parent->getOpcode() != ISD::INTRINSIC_VOID && // nontemporal stores
Parent->getOpcode() != X86ISD::TLSCALL) { // Fixme
unsigned AddrSpace =
cast<MemSDNode>(Parent)->getPointerInfo().getAddrSpace();
// AddrSpace 256 -> GS, 257 -> FS.
if (AddrSpace == 256)
AM.Segment = CurDAG->getRegister(X86::GS, MVT::i16);
if (AddrSpace == 257)
AM.Segment = CurDAG->getRegister(X86::FS, MVT::i16);
}
if (MatchAddress(N, AM))
return false;
EVT VT = N.getValueType();
if (AM.BaseType == X86ISelAddressMode::RegBase) {
if (!AM.Base_Reg.getNode())
AM.Base_Reg = CurDAG->getRegister(0, VT);
}
if (!AM.IndexReg.getNode())
AM.IndexReg = CurDAG->getRegister(0, VT);
getAddressOperands(AM, Base, Scale, Index, Disp, Segment);
return true;
}
/// SelectScalarSSELoad - Match a scalar SSE load. In particular, we want to
/// match a load whose top elements are either undef or zeros. The load flavor
/// is derived from the type of N, which is either v4f32 or v2f64.
///
/// We also return:
/// PatternChainNode: this is the matched node that has a chain input and
/// output.
bool X86DAGToDAGISel::SelectScalarSSELoad(SDNode *Root,
SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index,
SDValue &Disp, SDValue &Segment,
SDValue &PatternNodeWithChain) {
if (N.getOpcode() == ISD::SCALAR_TO_VECTOR) {
PatternNodeWithChain = N.getOperand(0);
if (ISD::isNON_EXTLoad(PatternNodeWithChain.getNode()) &&
PatternNodeWithChain.hasOneUse() &&
IsProfitableToFold(N.getOperand(0), N.getNode(), Root) &&
IsLegalToFold(N.getOperand(0), N.getNode(), Root, OptLevel)) {
LoadSDNode *LD = cast<LoadSDNode>(PatternNodeWithChain);
if (!SelectAddr(LD, LD->getBasePtr(), Base, Scale, Index, Disp, Segment))
return false;
return true;
}
}
// Also handle the case where we explicitly require zeros in the top
// elements. This is a vector shuffle from the zero vector.
if (N.getOpcode() == X86ISD::VZEXT_MOVL && N.getNode()->hasOneUse() &&
// Check to see if the top elements are all zeros (or bitcast of zeros).
N.getOperand(0).getOpcode() == ISD::SCALAR_TO_VECTOR &&
N.getOperand(0).getNode()->hasOneUse() &&
ISD::isNON_EXTLoad(N.getOperand(0).getOperand(0).getNode()) &&
N.getOperand(0).getOperand(0).hasOneUse() &&
IsProfitableToFold(N.getOperand(0), N.getNode(), Root) &&
IsLegalToFold(N.getOperand(0), N.getNode(), Root, OptLevel)) {
// Okay, this is a zero extending load. Fold it.
LoadSDNode *LD = cast<LoadSDNode>(N.getOperand(0).getOperand(0));
if (!SelectAddr(LD, LD->getBasePtr(), Base, Scale, Index, Disp, Segment))
return false;
PatternNodeWithChain = SDValue(LD, 0);
return true;
}
return false;
}
/// SelectLEAAddr - it calls SelectAddr and determines if the maximal addressing
/// mode it matches can be cost effectively emitted as an LEA instruction.
bool X86DAGToDAGISel::SelectLEAAddr(SDValue N,
SDValue &Base, SDValue &Scale,
SDValue &Index, SDValue &Disp,
SDValue &Segment) {
X86ISelAddressMode AM;
// Set AM.Segment to prevent MatchAddress from using one. LEA doesn't support
// segments.
SDValue Copy = AM.Segment;
SDValue T = CurDAG->getRegister(0, MVT::i32);
AM.Segment = T;
if (MatchAddress(N, AM))
return false;
assert (T == AM.Segment);
AM.Segment = Copy;
EVT VT = N.getValueType();
unsigned Complexity = 0;
if (AM.BaseType == X86ISelAddressMode::RegBase)
if (AM.Base_Reg.getNode())
Complexity = 1;
else
AM.Base_Reg = CurDAG->getRegister(0, VT);
else if (AM.BaseType == X86ISelAddressMode::FrameIndexBase)
Complexity = 4;
if (AM.IndexReg.getNode())
Complexity++;
else
AM.IndexReg = CurDAG->getRegister(0, VT);
// Don't match just leal(,%reg,2). It's cheaper to do addl %reg, %reg, or with
// a simple shift.
if (AM.Scale > 1)
Complexity++;
// FIXME: We are artificially lowering the criteria to turn ADD %reg, $GA
// to a LEA. This is determined with some expermentation but is by no means
// optimal (especially for code size consideration). LEA is nice because of
// its three-address nature. Tweak the cost function again when we can run
// convertToThreeAddress() at register allocation time.
if (AM.hasSymbolicDisplacement()) {
// For X86-64, we should always use lea to materialize RIP relative
// addresses.
if (Subtarget->is64Bit())
Complexity = 4;
else
Complexity += 2;
}
if (AM.Disp && (AM.Base_Reg.getNode() || AM.IndexReg.getNode()))
Complexity++;
// If it isn't worth using an LEA, reject it.
if (Complexity <= 2)
return false;
getAddressOperands(AM, Base, Scale, Index, Disp, Segment);
return true;
}
/// SelectTLSADDRAddr - This is only run on TargetGlobalTLSAddress nodes.
bool X86DAGToDAGISel::SelectTLSADDRAddr(SDValue N, SDValue &Base,
SDValue &Scale, SDValue &Index,
SDValue &Disp, SDValue &Segment) {
assert(N.getOpcode() == ISD::TargetGlobalTLSAddress);
const GlobalAddressSDNode *GA = cast<GlobalAddressSDNode>(N);
X86ISelAddressMode AM;
AM.GV = GA->getGlobal();
AM.Disp += GA->getOffset();
AM.Base_Reg = CurDAG->getRegister(0, N.getValueType());
AM.SymbolFlags = GA->getTargetFlags();
if (N.getValueType() == MVT::i32) {
AM.Scale = 1;
AM.IndexReg = CurDAG->getRegister(X86::EBX, MVT::i32);
} else {
AM.IndexReg = CurDAG->getRegister(0, MVT::i64);
}
getAddressOperands(AM, Base, Scale, Index, Disp, Segment);
return true;
}
bool X86DAGToDAGISel::TryFoldLoad(SDNode *P, SDValue N,
SDValue &Base, SDValue &Scale,
SDValue &Index, SDValue &Disp,
SDValue &Segment) {
if (!ISD::isNON_EXTLoad(N.getNode()) ||
!IsProfitableToFold(N, P, P) ||
!IsLegalToFold(N, P, P, OptLevel))
return false;
return SelectAddr(N.getNode(),
N.getOperand(1), Base, Scale, Index, Disp, Segment);
}
/// getGlobalBaseReg - Return an SDNode that returns the value of
/// the global base register. Output instructions required to
/// initialize the global base register, if necessary.
///
SDNode *X86DAGToDAGISel::getGlobalBaseReg() {
unsigned GlobalBaseReg = getInstrInfo()->getGlobalBaseReg(MF);
return CurDAG->getRegister(GlobalBaseReg, TLI.getPointerTy()).getNode();
}
SDNode *X86DAGToDAGISel::SelectAtomic64(SDNode *Node, unsigned Opc) {
SDValue Chain = Node->getOperand(0);
SDValue In1 = Node->getOperand(1);
SDValue In2L = Node->getOperand(2);
SDValue In2H = Node->getOperand(3);
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4;
if (!SelectAddr(Node, In1, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4))
return NULL;
MachineSDNode::mmo_iterator MemOp = MF->allocateMemRefsArray(1);
MemOp[0] = cast<MemSDNode>(Node)->getMemOperand();
const SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, In2L, In2H, Chain};
SDNode *ResNode = CurDAG->getMachineNode(Opc, Node->getDebugLoc(),
MVT::i32, MVT::i32, MVT::Other, Ops,
array_lengthof(Ops));
cast<MachineSDNode>(ResNode)->setMemRefs(MemOp, MemOp + 1);
return ResNode;
}
// FIXME: Figure out some way to unify this with the 'or' and other code
// below.
SDNode *X86DAGToDAGISel::SelectAtomicLoadAdd(SDNode *Node, EVT NVT) {
if (Node->hasAnyUseOfValue(0))
return 0;
// Optimize common patterns for __sync_add_and_fetch and
// __sync_sub_and_fetch where the result is not used. This allows us
// to use "lock" version of add, sub, inc, dec instructions.
// FIXME: Do not use special instructions but instead add the "lock"
// prefix to the target node somehow. The extra information will then be
// transferred to machine instruction and it denotes the prefix.
SDValue Chain = Node->getOperand(0);
SDValue Ptr = Node->getOperand(1);
SDValue Val = Node->getOperand(2);
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4;
if (!SelectAddr(Node, Ptr, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4))
return 0;
bool isInc = false, isDec = false, isSub = false, isCN = false;
ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Val);
if (CN && CN->getSExtValue() == (int32_t)CN->getSExtValue()) {
isCN = true;
int64_t CNVal = CN->getSExtValue();
if (CNVal == 1)
isInc = true;
else if (CNVal == -1)
isDec = true;
else if (CNVal >= 0)
Val = CurDAG->getTargetConstant(CNVal, NVT);
else {
isSub = true;
Val = CurDAG->getTargetConstant(-CNVal, NVT);
}
} else if (Val.hasOneUse() &&
Val.getOpcode() == ISD::SUB &&
X86::isZeroNode(Val.getOperand(0))) {
isSub = true;
Val = Val.getOperand(1);
}
DebugLoc dl = Node->getDebugLoc();
unsigned Opc = 0;
switch (NVT.getSimpleVT().SimpleTy) {
default: return 0;
case MVT::i8:
if (isInc)
Opc = X86::LOCK_INC8m;
else if (isDec)
Opc = X86::LOCK_DEC8m;
else if (isSub) {
if (isCN)
Opc = X86::LOCK_SUB8mi;
else
Opc = X86::LOCK_SUB8mr;
} else {
if (isCN)
Opc = X86::LOCK_ADD8mi;
else
Opc = X86::LOCK_ADD8mr;
}
break;
case MVT::i16:
if (isInc)
Opc = X86::LOCK_INC16m;
else if (isDec)
Opc = X86::LOCK_DEC16m;
else if (isSub) {
if (isCN) {
if (immSext8(Val.getNode()))
Opc = X86::LOCK_SUB16mi8;
else
Opc = X86::LOCK_SUB16mi;
} else
Opc = X86::LOCK_SUB16mr;
} else {
if (isCN) {
if (immSext8(Val.getNode()))
Opc = X86::LOCK_ADD16mi8;
else
Opc = X86::LOCK_ADD16mi;
} else
Opc = X86::LOCK_ADD16mr;
}
break;
case MVT::i32:
if (isInc)
Opc = X86::LOCK_INC32m;
else if (isDec)
Opc = X86::LOCK_DEC32m;
else if (isSub) {
if (isCN) {
if (immSext8(Val.getNode()))
Opc = X86::LOCK_SUB32mi8;
else
Opc = X86::LOCK_SUB32mi;
} else
Opc = X86::LOCK_SUB32mr;
} else {
if (isCN) {
if (immSext8(Val.getNode()))
Opc = X86::LOCK_ADD32mi8;
else
Opc = X86::LOCK_ADD32mi;
} else
Opc = X86::LOCK_ADD32mr;
}
break;
case MVT::i64:
if (isInc)
Opc = X86::LOCK_INC64m;
else if (isDec)
Opc = X86::LOCK_DEC64m;
else if (isSub) {
Opc = X86::LOCK_SUB64mr;
if (isCN) {
if (immSext8(Val.getNode()))
Opc = X86::LOCK_SUB64mi8;
else if (i64immSExt32(Val.getNode()))
Opc = X86::LOCK_SUB64mi32;
}
} else {
Opc = X86::LOCK_ADD64mr;
if (isCN) {
if (immSext8(Val.getNode()))
Opc = X86::LOCK_ADD64mi8;
else if (i64immSExt32(Val.getNode()))
Opc = X86::LOCK_ADD64mi32;
}
}
break;
}
SDValue Undef = SDValue(CurDAG->getMachineNode(TargetOpcode::IMPLICIT_DEF,
dl, NVT), 0);
MachineSDNode::mmo_iterator MemOp = MF->allocateMemRefsArray(1);
MemOp[0] = cast<MemSDNode>(Node)->getMemOperand();
if (isInc || isDec) {
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Chain };
SDValue Ret = SDValue(CurDAG->getMachineNode(Opc, dl, MVT::Other, Ops, 6), 0);
cast<MachineSDNode>(Ret)->setMemRefs(MemOp, MemOp + 1);
SDValue RetVals[] = { Undef, Ret };
return CurDAG->getMergeValues(RetVals, 2, dl).getNode();
} else {
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Val, Chain };
SDValue Ret = SDValue(CurDAG->getMachineNode(Opc, dl, MVT::Other, Ops, 7), 0);
cast<MachineSDNode>(Ret)->setMemRefs(MemOp, MemOp + 1);
SDValue RetVals[] = { Undef, Ret };
return CurDAG->getMergeValues(RetVals, 2, dl).getNode();
}
}
enum AtomicOpc {
OR,
AND,
XOR,
AtomicOpcEnd
};
enum AtomicSz {
ConstantI8,
I8,
SextConstantI16,
ConstantI16,
I16,
SextConstantI32,
ConstantI32,
I32,
SextConstantI64,
ConstantI64,
I64,
AtomicSzEnd
};
static const uint16_t AtomicOpcTbl[AtomicOpcEnd][AtomicSzEnd] = {
{
X86::LOCK_OR8mi,
X86::LOCK_OR8mr,
X86::LOCK_OR16mi8,
X86::LOCK_OR16mi,
X86::LOCK_OR16mr,
X86::LOCK_OR32mi8,
X86::LOCK_OR32mi,
X86::LOCK_OR32mr,
X86::LOCK_OR64mi8,
X86::LOCK_OR64mi32,
X86::LOCK_OR64mr
},
{
X86::LOCK_AND8mi,
X86::LOCK_AND8mr,
X86::LOCK_AND16mi8,
X86::LOCK_AND16mi,
X86::LOCK_AND16mr,
X86::LOCK_AND32mi8,
X86::LOCK_AND32mi,
X86::LOCK_AND32mr,
X86::LOCK_AND64mi8,
X86::LOCK_AND64mi32,
X86::LOCK_AND64mr
},
{
X86::LOCK_XOR8mi,
X86::LOCK_XOR8mr,
X86::LOCK_XOR16mi8,
X86::LOCK_XOR16mi,
X86::LOCK_XOR16mr,
X86::LOCK_XOR32mi8,
X86::LOCK_XOR32mi,
X86::LOCK_XOR32mr,
X86::LOCK_XOR64mi8,
X86::LOCK_XOR64mi32,
X86::LOCK_XOR64mr
}
};
SDNode *X86DAGToDAGISel::SelectAtomicLoadArith(SDNode *Node, EVT NVT) {
if (Node->hasAnyUseOfValue(0))
return 0;
// Optimize common patterns for __sync_or_and_fetch and similar arith
// operations where the result is not used. This allows us to use the "lock"
// version of the arithmetic instruction.
// FIXME: Same as for 'add' and 'sub', try to merge those down here.
SDValue Chain = Node->getOperand(0);
SDValue Ptr = Node->getOperand(1);
SDValue Val = Node->getOperand(2);
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4;
if (!SelectAddr(Node, Ptr, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4))
return 0;
// Which index into the table.
enum AtomicOpc Op;
switch (Node->getOpcode()) {
case ISD::ATOMIC_LOAD_OR:
Op = OR;
break;
case ISD::ATOMIC_LOAD_AND:
Op = AND;
break;
case ISD::ATOMIC_LOAD_XOR:
Op = XOR;
break;
default:
return 0;
}
bool isCN = false;
ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Val);
if (CN && (int32_t)CN->getSExtValue() == CN->getSExtValue()) {
isCN = true;
Val = CurDAG->getTargetConstant(CN->getSExtValue(), NVT);
}
unsigned Opc = 0;
switch (NVT.getSimpleVT().SimpleTy) {
default: return 0;
case MVT::i8:
if (isCN)
Opc = AtomicOpcTbl[Op][ConstantI8];
else
Opc = AtomicOpcTbl[Op][I8];
break;
case MVT::i16:
if (isCN) {
if (immSext8(Val.getNode()))
Opc = AtomicOpcTbl[Op][SextConstantI16];
else
Opc = AtomicOpcTbl[Op][ConstantI16];
} else
Opc = AtomicOpcTbl[Op][I16];
break;
case MVT::i32:
if (isCN) {
if (immSext8(Val.getNode()))
Opc = AtomicOpcTbl[Op][SextConstantI32];
else
Opc = AtomicOpcTbl[Op][ConstantI32];
} else
Opc = AtomicOpcTbl[Op][I32];
break;
case MVT::i64:
Opc = AtomicOpcTbl[Op][I64];
if (isCN) {
if (immSext8(Val.getNode()))
Opc = AtomicOpcTbl[Op][SextConstantI64];
else if (i64immSExt32(Val.getNode()))
Opc = AtomicOpcTbl[Op][ConstantI64];
}
break;
}
assert(Opc != 0 && "Invalid arith lock transform!");
DebugLoc dl = Node->getDebugLoc();
SDValue Undef = SDValue(CurDAG->getMachineNode(TargetOpcode::IMPLICIT_DEF,
dl, NVT), 0);
MachineSDNode::mmo_iterator MemOp = MF->allocateMemRefsArray(1);
MemOp[0] = cast<MemSDNode>(Node)->getMemOperand();
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Val, Chain };
SDValue Ret = SDValue(CurDAG->getMachineNode(Opc, dl, MVT::Other, Ops, 7), 0);
cast<MachineSDNode>(Ret)->setMemRefs(MemOp, MemOp + 1);
SDValue RetVals[] = { Undef, Ret };
return CurDAG->getMergeValues(RetVals, 2, dl).getNode();
}
/// HasNoSignedComparisonUses - Test whether the given X86ISD::CMP node has
/// any uses which require the SF or OF bits to be accurate.
static bool HasNoSignedComparisonUses(SDNode *N) {
// Examine each user of the node.
for (SDNode::use_iterator UI = N->use_begin(),
UE = N->use_end(); UI != UE; ++UI) {
// Only examine CopyToReg uses.
if (UI->getOpcode() != ISD::CopyToReg)
return false;
// Only examine CopyToReg uses that copy to EFLAGS.
if (cast<RegisterSDNode>(UI->getOperand(1))->getReg() !=
X86::EFLAGS)
return false;
// Examine each user of the CopyToReg use.
for (SDNode::use_iterator FlagUI = UI->use_begin(),
FlagUE = UI->use_end(); FlagUI != FlagUE; ++FlagUI) {
// Only examine the Flag result.
if (FlagUI.getUse().getResNo() != 1) continue;
// Anything unusual: assume conservatively.
if (!FlagUI->isMachineOpcode()) return false;
// Examine the opcode of the user.
switch (FlagUI->getMachineOpcode()) {
// These comparisons don't treat the most significant bit specially.
case X86::SETAr: case X86::SETAEr: case X86::SETBr: case X86::SETBEr:
case X86::SETEr: case X86::SETNEr: case X86::SETPr: case X86::SETNPr:
case X86::SETAm: case X86::SETAEm: case X86::SETBm: case X86::SETBEm:
case X86::SETEm: case X86::SETNEm: case X86::SETPm: case X86::SETNPm:
case X86::JA_4: case X86::JAE_4: case X86::JB_4: case X86::JBE_4:
case X86::JE_4: case X86::JNE_4: case X86::JP_4: case X86::JNP_4:
case X86::CMOVA16rr: case X86::CMOVA16rm:
case X86::CMOVA32rr: case X86::CMOVA32rm:
case X86::CMOVA64rr: case X86::CMOVA64rm:
case X86::CMOVAE16rr: case X86::CMOVAE16rm:
case X86::CMOVAE32rr: case X86::CMOVAE32rm:
case X86::CMOVAE64rr: case X86::CMOVAE64rm:
case X86::CMOVB16rr: case X86::CMOVB16rm:
case X86::CMOVB32rr: case X86::CMOVB32rm:
case X86::CMOVB64rr: case X86::CMOVB64rm:
case X86::CMOVBE16rr: case X86::CMOVBE16rm:
case X86::CMOVBE32rr: case X86::CMOVBE32rm:
case X86::CMOVBE64rr: case X86::CMOVBE64rm:
case X86::CMOVE16rr: case X86::CMOVE16rm:
case X86::CMOVE32rr: case X86::CMOVE32rm:
case X86::CMOVE64rr: case X86::CMOVE64rm:
case X86::CMOVNE16rr: case X86::CMOVNE16rm:
case X86::CMOVNE32rr: case X86::CMOVNE32rm:
case X86::CMOVNE64rr: case X86::CMOVNE64rm:
case X86::CMOVNP16rr: case X86::CMOVNP16rm:
case X86::CMOVNP32rr: case X86::CMOVNP32rm:
case X86::CMOVNP64rr: case X86::CMOVNP64rm:
case X86::CMOVP16rr: case X86::CMOVP16rm:
case X86::CMOVP32rr: case X86::CMOVP32rm:
case X86::CMOVP64rr: case X86::CMOVP64rm:
continue;
// Anything else: assume conservatively.
default: return false;
}
}
}
return true;
}
/// isLoadIncOrDecStore - Check whether or not the chain ending in StoreNode
/// is suitable for doing the {load; increment or decrement; store} to modify
/// transformation.
static bool isLoadIncOrDecStore(StoreSDNode *StoreNode, unsigned Opc,
SDValue &StoredVal) {
// is the value stored the result of a DEC or INC?
if (!(Opc == X86ISD::DEC || Opc == X86ISD::INC)) return false;
// is the chain predecessor to the store a load?
SDValue Chain = StoreNode->getChain();
if (Chain->getOpcode() != ISD::LOAD) return false;
// is the size of the value one that we can handle? (i.e. 64, 32, 16, or 8)
LoadSDNode *LoadNode = cast<LoadSDNode>(Chain.getNode());
EVT LdVT = LoadNode->getMemoryVT();
if (LdVT != MVT::i64 && LdVT != MVT::i32 && LdVT != MVT::i16 &&
LdVT != MVT::i8)
return false;
// quick check of whether the store is simple
SDValue Undef = StoreNode->getOffset();
if (Undef->getOpcode() != ISD::UNDEF) return false;
// is the stored value result 0 of the load?
if (StoredVal.getResNo() != 0) return false;
// are there other uses of the loaded value than the inc or dec?
if (!StoredVal.getNode()->hasNUsesOfValue(1, 0)) return false;
// is there exactly one use of the load?
if (!LoadNode->hasNUsesOfValue(1, 0)) return false;
// are the load and store connected by the chain?
if (StoredVal->getOperand(0).getNode() != LoadNode) return false;
//OPC_CheckPredicate, 1, // Predicate_nontemporalstore
if (StoreNode->isNonTemporal())
return false;
// is the address of the store the same as the load?
SDValue Address = StoreNode->getBasePtr();
if (LoadNode->getBasePtr() != Address ||
LoadNode->getOffset() != Undef)
return false;
// is the load non-extending and non-indexed?
if (!ISD::isNormalLoad(LoadNode))
return false;
// is the store non-extending and non-indexed?
if (!ISD::isNormalStore(StoreNode))
return false;
// check load chain has only one use (from the store)
if (!Chain.hasOneUse())
return false;
return true;
}
/// getFusedLdStOpcode - Get the appropriate X86 opcode for an in memory
/// increment or decrement. Opc should be X86ISD::DEC or X86ISD::INC.
static unsigned getFusedLdStOpcode(EVT &LdVT, unsigned Opc) {
if (Opc == X86ISD::DEC) {
if (LdVT == MVT::i64) return X86::DEC64m;
if (LdVT == MVT::i32) return X86::DEC32m;
if (LdVT == MVT::i16) return X86::DEC16m;
if (LdVT == MVT::i8) return X86::DEC8m;
} else {
assert(Opc == X86ISD::INC && "unrecognized opcode");
if (LdVT == MVT::i64) return X86::INC64m;
if (LdVT == MVT::i32) return X86::INC32m;
if (LdVT == MVT::i16) return X86::INC16m;
if (LdVT == MVT::i8) return X86::INC8m;
}
llvm_unreachable("unrecognized size for LdVT");
}
SDNode *X86DAGToDAGISel::Select(SDNode *Node) {
EVT NVT = Node->getValueType(0);
unsigned Opc, MOpc;
unsigned Opcode = Node->getOpcode();
DebugLoc dl = Node->getDebugLoc();
DEBUG(dbgs() << "Selecting: "; Node->dump(CurDAG); dbgs() << '\n');
if (Node->isMachineOpcode()) {
DEBUG(dbgs() << "== "; Node->dump(CurDAG); dbgs() << '\n');
return NULL; // Already selected.
}
switch (Opcode) {
default: break;
case X86ISD::GlobalBaseReg:
return getGlobalBaseReg();
case X86ISD::ATOMOR64_DAG:
return SelectAtomic64(Node, X86::ATOMOR6432);
case X86ISD::ATOMXOR64_DAG:
return SelectAtomic64(Node, X86::ATOMXOR6432);
case X86ISD::ATOMADD64_DAG:
return SelectAtomic64(Node, X86::ATOMADD6432);
case X86ISD::ATOMSUB64_DAG:
return SelectAtomic64(Node, X86::ATOMSUB6432);
case X86ISD::ATOMNAND64_DAG:
return SelectAtomic64(Node, X86::ATOMNAND6432);
case X86ISD::ATOMAND64_DAG:
return SelectAtomic64(Node, X86::ATOMAND6432);
case X86ISD::ATOMSWAP64_DAG:
return SelectAtomic64(Node, X86::ATOMSWAP6432);
case ISD::ATOMIC_LOAD_ADD: {
SDNode *RetVal = SelectAtomicLoadAdd(Node, NVT);
if (RetVal)
return RetVal;
break;
}
case ISD::ATOMIC_LOAD_XOR:
case ISD::ATOMIC_LOAD_AND:
case ISD::ATOMIC_LOAD_OR: {
SDNode *RetVal = SelectAtomicLoadArith(Node, NVT);
if (RetVal)
return RetVal;
break;
}
case ISD::AND:
case ISD::OR:
case ISD::XOR: {
// For operations of the form (x << C1) op C2, check if we can use a smaller
// encoding for C2 by transforming it into (x op (C2>>C1)) << C1.
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
if (N0->getOpcode() != ISD::SHL || !N0->hasOneUse())
break;
// i8 is unshrinkable, i16 should be promoted to i32.
if (NVT != MVT::i32 && NVT != MVT::i64)
break;
ConstantSDNode *Cst = dyn_cast<ConstantSDNode>(N1);
ConstantSDNode *ShlCst = dyn_cast<ConstantSDNode>(N0->getOperand(1));
if (!Cst || !ShlCst)
break;
int64_t Val = Cst->getSExtValue();
uint64_t ShlVal = ShlCst->getZExtValue();
// Make sure that we don't change the operation by removing bits.
// This only matters for OR and XOR, AND is unaffected.
if (Opcode != ISD::AND && ((Val >> ShlVal) << ShlVal) != Val)
break;
unsigned ShlOp, Op = 0;
EVT CstVT = NVT;
// Check the minimum bitwidth for the new constant.
// TODO: AND32ri is the same as AND64ri32 with zext imm.
// TODO: MOV32ri+OR64r is cheaper than MOV64ri64+OR64rr
// TODO: Using 16 and 8 bit operations is also possible for or32 & xor32.
if (!isInt<8>(Val) && isInt<8>(Val >> ShlVal))
CstVT = MVT::i8;
else if (!isInt<32>(Val) && isInt<32>(Val >> ShlVal))
CstVT = MVT::i32;
// Bail if there is no smaller encoding.
if (NVT == CstVT)
break;
switch (NVT.getSimpleVT().SimpleTy) {
default: llvm_unreachable("Unsupported VT!");
case MVT::i32:
assert(CstVT == MVT::i8);
ShlOp = X86::SHL32ri;
switch (Opcode) {
case ISD::AND: Op = X86::AND32ri8; break;
case ISD::OR: Op = X86::OR32ri8; break;
case ISD::XOR: Op = X86::XOR32ri8; break;
}
break;
case MVT::i64:
assert(CstVT == MVT::i8 || CstVT == MVT::i32);
ShlOp = X86::SHL64ri;
switch (Opcode) {
case ISD::AND: Op = CstVT==MVT::i8? X86::AND64ri8 : X86::AND64ri32; break;
case ISD::OR: Op = CstVT==MVT::i8? X86::OR64ri8 : X86::OR64ri32; break;
case ISD::XOR: Op = CstVT==MVT::i8? X86::XOR64ri8 : X86::XOR64ri32; break;
}
break;
}
// Emit the smaller op and the shift.
SDValue NewCst = CurDAG->getTargetConstant(Val >> ShlVal, CstVT);
SDNode *New = CurDAG->getMachineNode(Op, dl, NVT, N0->getOperand(0),NewCst);
return CurDAG->SelectNodeTo(Node, ShlOp, NVT, SDValue(New, 0),
getI8Imm(ShlVal));
}
case X86ISD::UMUL: {
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
unsigned LoReg;
switch (NVT.getSimpleVT().SimpleTy) {
default: llvm_unreachable("Unsupported VT!");
case MVT::i8: LoReg = X86::AL; Opc = X86::MUL8r; break;
case MVT::i16: LoReg = X86::AX; Opc = X86::MUL16r; break;
case MVT::i32: LoReg = X86::EAX; Opc = X86::MUL32r; break;
case MVT::i64: LoReg = X86::RAX; Opc = X86::MUL64r; break;
}
SDValue InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, LoReg,
N0, SDValue()).getValue(1);
SDVTList VTs = CurDAG->getVTList(NVT, NVT, MVT::i32);
SDValue Ops[] = {N1, InFlag};
SDNode *CNode = CurDAG->getMachineNode(Opc, dl, VTs, Ops, 2);
ReplaceUses(SDValue(Node, 0), SDValue(CNode, 0));
ReplaceUses(SDValue(Node, 1), SDValue(CNode, 1));
ReplaceUses(SDValue(Node, 2), SDValue(CNode, 2));
return NULL;
}
case ISD::SMUL_LOHI:
case ISD::UMUL_LOHI: {
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
bool isSigned = Opcode == ISD::SMUL_LOHI;
if (!isSigned) {
switch (NVT.getSimpleVT().SimpleTy) {
default: llvm_unreachable("Unsupported VT!");
case MVT::i8: Opc = X86::MUL8r; MOpc = X86::MUL8m; break;
case MVT::i16: Opc = X86::MUL16r; MOpc = X86::MUL16m; break;
case MVT::i32: Opc = X86::MUL32r; MOpc = X86::MUL32m; break;
case MVT::i64: Opc = X86::MUL64r; MOpc = X86::MUL64m; break;
}
} else {
switch (NVT.getSimpleVT().SimpleTy) {
default: llvm_unreachable("Unsupported VT!");
case MVT::i8: Opc = X86::IMUL8r; MOpc = X86::IMUL8m; break;
case MVT::i16: Opc = X86::IMUL16r; MOpc = X86::IMUL16m; break;
case MVT::i32: Opc = X86::IMUL32r; MOpc = X86::IMUL32m; break;
case MVT::i64: Opc = X86::IMUL64r; MOpc = X86::IMUL64m; break;
}
}
unsigned LoReg, HiReg;
switch (NVT.getSimpleVT().SimpleTy) {
default: llvm_unreachable("Unsupported VT!");
case MVT::i8: LoReg = X86::AL; HiReg = X86::AH; break;
case MVT::i16: LoReg = X86::AX; HiReg = X86::DX; break;
case MVT::i32: LoReg = X86::EAX; HiReg = X86::EDX; break;
case MVT::i64: LoReg = X86::RAX; HiReg = X86::RDX; break;
}
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4;
bool foldedLoad = TryFoldLoad(Node, N1, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4);
// Multiply is commmutative.
if (!foldedLoad) {
foldedLoad = TryFoldLoad(Node, N0, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4);
if (foldedLoad)
std::swap(N0, N1);
}
SDValue InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, LoReg,
N0, SDValue()).getValue(1);
if (foldedLoad) {
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, N1.getOperand(0),
InFlag };
SDNode *CNode =
CurDAG->getMachineNode(MOpc, dl, MVT::Other, MVT::Glue, Ops,
array_lengthof(Ops));
InFlag = SDValue(CNode, 1);
// Update the chain.
ReplaceUses(N1.getValue(1), SDValue(CNode, 0));
} else {
SDNode *CNode = CurDAG->getMachineNode(Opc, dl, MVT::Glue, N1, InFlag);
InFlag = SDValue(CNode, 0);
}
// Prevent use of AH in a REX instruction by referencing AX instead.
if (HiReg == X86::AH && Subtarget->is64Bit() &&
!SDValue(Node, 1).use_empty()) {
SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
X86::AX, MVT::i16, InFlag);
InFlag = Result.getValue(2);
// Get the low part if needed. Don't use getCopyFromReg for aliasing
// registers.
if (!SDValue(Node, 0).use_empty())
ReplaceUses(SDValue(Node, 1),
CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Result));
// Shift AX down 8 bits.
Result = SDValue(CurDAG->getMachineNode(X86::SHR16ri, dl, MVT::i16,
Result,
CurDAG->getTargetConstant(8, MVT::i8)), 0);
// Then truncate it down to i8.
ReplaceUses(SDValue(Node, 1),
CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Result));
}
// Copy the low half of the result, if it is needed.
if (!SDValue(Node, 0).use_empty()) {
SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
LoReg, NVT, InFlag);
InFlag = Result.getValue(2);
ReplaceUses(SDValue(Node, 0), Result);
DEBUG(dbgs() << "=> "; Result.getNode()->dump(CurDAG); dbgs() << '\n');
}
// Copy the high half of the result, if it is needed.
if (!SDValue(Node, 1).use_empty()) {
SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
HiReg, NVT, InFlag);
InFlag = Result.getValue(2);
ReplaceUses(SDValue(Node, 1), Result);
DEBUG(dbgs() << "=> "; Result.getNode()->dump(CurDAG); dbgs() << '\n');
}
return NULL;
}
case ISD::SDIVREM:
case ISD::UDIVREM: {
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
bool isSigned = Opcode == ISD::SDIVREM;
if (!isSigned) {
switch (NVT.getSimpleVT().SimpleTy) {
default: llvm_unreachable("Unsupported VT!");
case MVT::i8: Opc = X86::DIV8r; MOpc = X86::DIV8m; break;
case MVT::i16: Opc = X86::DIV16r; MOpc = X86::DIV16m; break;
case MVT::i32: Opc = X86::DIV32r; MOpc = X86::DIV32m; break;
case MVT::i64: Opc = X86::DIV64r; MOpc = X86::DIV64m; break;
}
} else {
switch (NVT.getSimpleVT().SimpleTy) {
default: llvm_unreachable("Unsupported VT!");
case MVT::i8: Opc = X86::IDIV8r; MOpc = X86::IDIV8m; break;
case MVT::i16: Opc = X86::IDIV16r; MOpc = X86::IDIV16m; break;
case MVT::i32: Opc = X86::IDIV32r; MOpc = X86::IDIV32m; break;
case MVT::i64: Opc = X86::IDIV64r; MOpc = X86::IDIV64m; break;
}
}
unsigned LoReg, HiReg, ClrReg;
unsigned ClrOpcode, SExtOpcode;
switch (NVT.getSimpleVT().SimpleTy) {
default: llvm_unreachable("Unsupported VT!");
case MVT::i8:
LoReg = X86::AL; ClrReg = HiReg = X86::AH;
ClrOpcode = 0;
SExtOpcode = X86::CBW;
break;
case MVT::i16:
LoReg = X86::AX; HiReg = X86::DX;
ClrOpcode = X86::MOV16r0; ClrReg = X86::DX;
SExtOpcode = X86::CWD;
break;
case MVT::i32:
LoReg = X86::EAX; ClrReg = HiReg = X86::EDX;
ClrOpcode = X86::MOV32r0;
SExtOpcode = X86::CDQ;
break;
case MVT::i64:
LoReg = X86::RAX; ClrReg = HiReg = X86::RDX;
ClrOpcode = X86::MOV64r0;
SExtOpcode = X86::CQO;
break;
}
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4;
bool foldedLoad = TryFoldLoad(Node, N1, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4);
bool signBitIsZero = CurDAG->SignBitIsZero(N0);
SDValue InFlag;
if (NVT == MVT::i8 && (!isSigned || signBitIsZero)) {
// Special case for div8, just use a move with zero extension to AX to
// clear the upper 8 bits (AH).
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Move, Chain;
if (TryFoldLoad(Node, N0, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4)) {
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, N0.getOperand(0) };
Move =
SDValue(CurDAG->getMachineNode(X86::MOVZX32rm8, dl, MVT::i32,
MVT::Other, Ops,
array_lengthof(Ops)), 0);
Chain = Move.getValue(1);
ReplaceUses(N0.getValue(1), Chain);
} else {
Move =
SDValue(CurDAG->getMachineNode(X86::MOVZX32rr8, dl, MVT::i32, N0),0);
Chain = CurDAG->getEntryNode();
}
Chain = CurDAG->getCopyToReg(Chain, dl, X86::EAX, Move, SDValue());
InFlag = Chain.getValue(1);
} else {
InFlag =
CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl,
LoReg, N0, SDValue()).getValue(1);
if (isSigned && !signBitIsZero) {
// Sign extend the low part into the high part.
InFlag =
SDValue(CurDAG->getMachineNode(SExtOpcode, dl, MVT::Glue, InFlag),0);
} else {
// Zero out the high part, effectively zero extending the input.
SDValue ClrNode =
SDValue(CurDAG->getMachineNode(ClrOpcode, dl, NVT), 0);
InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, ClrReg,
ClrNode, InFlag).getValue(1);
}
}
if (foldedLoad) {
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, N1.getOperand(0),
InFlag };
SDNode *CNode =
CurDAG->getMachineNode(MOpc, dl, MVT::Other, MVT::Glue, Ops,
array_lengthof(Ops));
InFlag = SDValue(CNode, 1);
// Update the chain.
ReplaceUses(N1.getValue(1), SDValue(CNode, 0));
} else {
InFlag =
SDValue(CurDAG->getMachineNode(Opc, dl, MVT::Glue, N1, InFlag), 0);
}
// Prevent use of AH in a REX instruction by referencing AX instead.
// Shift it down 8 bits.
if (HiReg == X86::AH && Subtarget->is64Bit() &&
!SDValue(Node, 1).use_empty()) {
SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
X86::AX, MVT::i16, InFlag);
InFlag = Result.getValue(2);
// If we also need AL (the quotient), get it by extracting a subreg from
// Result. The fast register allocator does not like multiple CopyFromReg
// nodes using aliasing registers.
if (!SDValue(Node, 0).use_empty())
ReplaceUses(SDValue(Node, 0),
CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Result));
// Shift AX right by 8 bits instead of using AH.
Result = SDValue(CurDAG->getMachineNode(X86::SHR16ri, dl, MVT::i16,
Result,
CurDAG->getTargetConstant(8, MVT::i8)),
0);
ReplaceUses(SDValue(Node, 1),
CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Result));
}
// Copy the division (low) result, if it is needed.
if (!SDValue(Node, 0).use_empty()) {
SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
LoReg, NVT, InFlag);
InFlag = Result.getValue(2);
ReplaceUses(SDValue(Node, 0), Result);
DEBUG(dbgs() << "=> "; Result.getNode()->dump(CurDAG); dbgs() << '\n');
}
// Copy the remainder (high) result, if it is needed.
if (!SDValue(Node, 1).use_empty()) {
SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
HiReg, NVT, InFlag);
InFlag = Result.getValue(2);
ReplaceUses(SDValue(Node, 1), Result);
DEBUG(dbgs() << "=> "; Result.getNode()->dump(CurDAG); dbgs() << '\n');
}
return NULL;
}
case X86ISD::CMP: {
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
// Look for (X86cmp (and $op, $imm), 0) and see if we can convert it to
// use a smaller encoding.
if (N0.getOpcode() == ISD::TRUNCATE && N0.hasOneUse() &&
HasNoSignedComparisonUses(Node))
// Look past the truncate if CMP is the only use of it.
N0 = N0.getOperand(0);
if ((N0.getNode()->getOpcode() == ISD::AND ||
(N0.getResNo() == 0 && N0.getNode()->getOpcode() == X86ISD::AND)) &&
N0.getNode()->hasOneUse() &&
N0.getValueType() != MVT::i8 &&
X86::isZeroNode(N1)) {
ConstantSDNode *C = dyn_cast<ConstantSDNode>(N0.getNode()->getOperand(1));
if (!C) break;
// For example, convert "testl %eax, $8" to "testb %al, $8"
if ((C->getZExtValue() & ~UINT64_C(0xff)) == 0 &&
(!(C->getZExtValue() & 0x80) ||
HasNoSignedComparisonUses(Node))) {
SDValue Imm = CurDAG->getTargetConstant(C->getZExtValue(), MVT::i8);
SDValue Reg = N0.getNode()->getOperand(0);
// On x86-32, only the ABCD registers have 8-bit subregisters.
if (!Subtarget->is64Bit()) {
const TargetRegisterClass *TRC;
switch (N0.getValueType().getSimpleVT().SimpleTy) {
case MVT::i32: TRC = &X86::GR32_ABCDRegClass; break;
case MVT::i16: TRC = &X86::GR16_ABCDRegClass; break;
default: llvm_unreachable("Unsupported TEST operand type!");
}
SDValue RC = CurDAG->getTargetConstant(TRC->getID(), MVT::i32);
Reg = SDValue(CurDAG->getMachineNode(X86::COPY_TO_REGCLASS, dl,
Reg.getValueType(), Reg, RC), 0);
}
// Extract the l-register.
SDValue Subreg = CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl,
MVT::i8, Reg);
// Emit a testb.
return CurDAG->getMachineNode(X86::TEST8ri, dl, MVT::i32, Subreg, Imm);
}
// For example, "testl %eax, $2048" to "testb %ah, $8".
if ((C->getZExtValue() & ~UINT64_C(0xff00)) == 0 &&
(!(C->getZExtValue() & 0x8000) ||
HasNoSignedComparisonUses(Node))) {
// Shift the immediate right by 8 bits.
SDValue ShiftedImm = CurDAG->getTargetConstant(C->getZExtValue() >> 8,
MVT::i8);
SDValue Reg = N0.getNode()->getOperand(0);
// Put the value in an ABCD register.
const TargetRegisterClass *TRC;
switch (N0.getValueType().getSimpleVT().SimpleTy) {
case MVT::i64: TRC = &X86::GR64_ABCDRegClass; break;
case MVT::i32: TRC = &X86::GR32_ABCDRegClass; break;
case MVT::i16: TRC = &X86::GR16_ABCDRegClass; break;
default: llvm_unreachable("Unsupported TEST operand type!");
}
SDValue RC = CurDAG->getTargetConstant(TRC->getID(), MVT::i32);
Reg = SDValue(CurDAG->getMachineNode(X86::COPY_TO_REGCLASS, dl,
Reg.getValueType(), Reg, RC), 0);
// Extract the h-register.
SDValue Subreg = CurDAG->getTargetExtractSubreg(X86::sub_8bit_hi, dl,
MVT::i8, Reg);
// Emit a testb. The EXTRACT_SUBREG becomes a COPY that can only
// target GR8_NOREX registers, so make sure the register class is
// forced.
return CurDAG->getMachineNode(X86::TEST8ri_NOREX, dl, MVT::i32,
Subreg, ShiftedImm);
}
// For example, "testl %eax, $32776" to "testw %ax, $32776".
if ((C->getZExtValue() & ~UINT64_C(0xffff)) == 0 &&
N0.getValueType() != MVT::i16 &&
(!(C->getZExtValue() & 0x8000) ||
HasNoSignedComparisonUses(Node))) {
SDValue Imm = CurDAG->getTargetConstant(C->getZExtValue(), MVT::i16);
SDValue Reg = N0.getNode()->getOperand(0);
// Extract the 16-bit subregister.
SDValue Subreg = CurDAG->getTargetExtractSubreg(X86::sub_16bit, dl,
MVT::i16, Reg);
// Emit a testw.
return CurDAG->getMachineNode(X86::TEST16ri, dl, MVT::i32, Subreg, Imm);
}
// For example, "testq %rax, $268468232" to "testl %eax, $268468232".
if ((C->getZExtValue() & ~UINT64_C(0xffffffff)) == 0 &&
N0.getValueType() == MVT::i64 &&
(!(C->getZExtValue() & 0x80000000) ||
HasNoSignedComparisonUses(Node))) {
SDValue Imm = CurDAG->getTargetConstant(C->getZExtValue(), MVT::i32);
SDValue Reg = N0.getNode()->getOperand(0);
// Extract the 32-bit subregister.
SDValue Subreg = CurDAG->getTargetExtractSubreg(X86::sub_32bit, dl,
MVT::i32, Reg);
// Emit a testl.
return CurDAG->getMachineNode(X86::TEST32ri, dl, MVT::i32, Subreg, Imm);
}
}
break;
}
case ISD::STORE: {
// Change a chain of {load; incr or dec; store} of the same value into
// a simple increment or decrement through memory of that value, if the
// uses of the modified value and its address are suitable.
// The DEC64m tablegen pattern is currently not able to match the case where
// the EFLAGS on the original DEC are used. (This also applies to
// {INC,DEC}X{64,32,16,8}.)
// We'll need to improve tablegen to allow flags to be transferred from a
// node in the pattern to the result node. probably with a new keyword
// for example, we have this
// def DEC64m : RI<0xFF, MRM1m, (outs), (ins i64mem:$dst), "dec{q}\t$dst",
// [(store (add (loadi64 addr:$dst), -1), addr:$dst),
// (implicit EFLAGS)]>;
// but maybe need something like this
// def DEC64m : RI<0xFF, MRM1m, (outs), (ins i64mem:$dst), "dec{q}\t$dst",
// [(store (add (loadi64 addr:$dst), -1), addr:$dst),
// (transferrable EFLAGS)]>;
StoreSDNode *StoreNode = cast<StoreSDNode>(Node);
SDValue StoredVal = StoreNode->getOperand(1);
unsigned Opc = StoredVal->getOpcode();
if (!isLoadIncOrDecStore(StoreNode, Opc, StoredVal)) break;
// Merge the input chains if they are not intra-pattern references.
SDValue Chain = StoreNode->getOperand(0);
LoadSDNode *LoadNode = cast<LoadSDNode>(Chain.getNode());
SDValue InputChain = LoadNode->getOperand(0);
SDValue Base, Scale, Index, Disp, Segment;
if (!SelectAddr(LoadNode, LoadNode->getBasePtr(),
Base, Scale, Index, Disp, Segment))
break;
MachineSDNode::mmo_iterator MemOp = MF->allocateMemRefsArray(2);
MemOp[0] = StoreNode->getMemOperand();
MemOp[1] = LoadNode->getMemOperand();
const SDValue Ops[] = { Base, Scale, Index, Disp, Segment, InputChain };
EVT LdVT = LoadNode->getMemoryVT();
unsigned newOpc = getFusedLdStOpcode(LdVT, Opc);
MachineSDNode *Result = CurDAG->getMachineNode(newOpc,
Node->getDebugLoc(),
MVT::i32, MVT::Other, Ops,
array_lengthof(Ops));
Result->setMemRefs(MemOp, MemOp + 2);
ReplaceUses(SDValue(StoreNode, 0), SDValue(Result, 1));
ReplaceUses(SDValue(StoredVal.getNode(), 1), SDValue(Result, 0));
return Result;
}
}
SDNode *ResNode = SelectCode(Node);
DEBUG(dbgs() << "=> ";
if (ResNode == NULL || ResNode == Node)
Node->dump(CurDAG);
else
ResNode->dump(CurDAG);
dbgs() << '\n');
return ResNode;
}
bool X86DAGToDAGISel::
SelectInlineAsmMemoryOperand(const SDValue &Op, char ConstraintCode,
std::vector<SDValue> &OutOps) {
SDValue Op0, Op1, Op2, Op3, Op4;
switch (ConstraintCode) {
case 'o': // offsetable ??
case 'v': // not offsetable ??
default: return true;
case 'm': // memory
if (!SelectAddr(0, Op, Op0, Op1, Op2, Op3, Op4))
return true;
break;
}
OutOps.push_back(Op0);
OutOps.push_back(Op1);
OutOps.push_back(Op2);
OutOps.push_back(Op3);
OutOps.push_back(Op4);
return false;
}
/// createX86ISelDag - This pass converts a legalized DAG into a
/// X86-specific DAG, ready for instruction scheduling.
///
FunctionPass *llvm::createX86ISelDag(X86TargetMachine &TM,
CodeGenOpt::Level OptLevel) {
return new X86DAGToDAGISel(TM, OptLevel);
}
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