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llvm-6502/lib/Target/X86/X86ISelDAGToDAG.cpp
Evan Cheng b3c334674d Allocating too large an array for ReachibilityMatrix. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29367 91177308-0d34-0410-b5e6-96231b3b80d8
2006-07-27 22:35:40 +00:00

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//===- X86ISelDAGToDAG.cpp - A DAG pattern matching inst selector for X86 -===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the Evan Cheng and 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 "isel"
#include "X86.h"
#include "X86InstrBuilder.h"
#include "X86ISelLowering.h"
#include "X86RegisterInfo.h"
#include "X86Subtarget.h"
#include "X86TargetMachine.h"
#include "llvm/GlobalValue.h"
#include "llvm/Instructions.h"
#include "llvm/Intrinsics.h"
#include "llvm/Support/CFG.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/SSARegMap.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Visibility.h"
#include "llvm/ADT/Statistic.h"
#include <iostream>
#include <list>
#include <set>
using namespace llvm;
//===----------------------------------------------------------------------===//
// Pattern Matcher Implementation
//===----------------------------------------------------------------------===//
namespace {
/// X86ISelAddressMode - This corresponds to X86AddressMode, but uses
/// SDOperand's instead of register numbers for the leaves of the matched
/// tree.
struct X86ISelAddressMode {
enum {
RegBase,
FrameIndexBase
} BaseType;
struct { // This is really a union, discriminated by BaseType!
SDOperand Reg;
int FrameIndex;
} Base;
unsigned Scale;
SDOperand IndexReg;
unsigned Disp;
GlobalValue *GV;
Constant *CP;
unsigned Align; // CP alignment.
X86ISelAddressMode()
: BaseType(RegBase), Scale(1), IndexReg(), Disp(0), GV(0),
CP(0), Align(0) {
}
};
}
namespace {
Statistic<>
NumFPKill("x86-codegen", "Number of FP_REG_KILL instructions added");
//===--------------------------------------------------------------------===//
/// ISel - X86 specific code to select X86 machine instructions for
/// SelectionDAG operations.
///
class VISIBILITY_HIDDEN X86DAGToDAGISel : public SelectionDAGISel {
/// ContainsFPCode - Every instruction we select that uses or defines a FP
/// register should set this to true.
bool ContainsFPCode;
/// X86Lowering - This object fully describes how to lower LLVM code to an
/// X86-specific SelectionDAG.
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;
unsigned GlobalBaseReg;
public:
X86DAGToDAGISel(X86TargetMachine &TM)
: SelectionDAGISel(X86Lowering),
X86Lowering(*TM.getTargetLowering()),
Subtarget(&TM.getSubtarget<X86Subtarget>()),
DAGSize(0), ReachibilityMatrix(NULL) {}
virtual bool runOnFunction(Function &Fn) {
// Make sure we re-emit a set of the global base reg if necessary
GlobalBaseReg = 0;
return SelectionDAGISel::runOnFunction(Fn);
}
virtual const char *getPassName() const {
return "X86 DAG->DAG Instruction Selection";
}
/// InstructionSelectBasicBlock - This callback is invoked by
/// SelectionDAGISel when it has created a SelectionDAG for us to codegen.
virtual void InstructionSelectBasicBlock(SelectionDAG &DAG);
virtual void EmitFunctionEntryCode(Function &Fn, MachineFunction &MF);
virtual bool IsFoldableBy(SDNode *N, SDNode *U);
// Include the pieces autogenerated from the target description.
#include "X86GenDAGISel.inc"
private:
void DetermineTopologicalOrdering();
void DeterminReachibility(SDNode *f, SDNode *t);
void Select(SDOperand &Result, SDOperand N);
bool MatchAddress(SDOperand N, X86ISelAddressMode &AM, bool isRoot = true);
bool SelectAddr(SDOperand N, SDOperand &Base, SDOperand &Scale,
SDOperand &Index, SDOperand &Disp);
bool SelectLEAAddr(SDOperand N, SDOperand &Base, SDOperand &Scale,
SDOperand &Index, SDOperand &Disp);
bool TryFoldLoad(SDOperand P, SDOperand N,
SDOperand &Base, SDOperand &Scale,
SDOperand &Index, SDOperand &Disp);
/// SelectInlineAsmMemoryOperand - Implement addressing mode selection for
/// inline asm expressions.
virtual bool SelectInlineAsmMemoryOperand(const SDOperand &Op,
char ConstraintCode,
std::vector<SDOperand> &OutOps,
SelectionDAG &DAG);
void EmitSpecialCodeForMain(MachineBasicBlock *BB, MachineFrameInfo *MFI);
inline void getAddressOperands(X86ISelAddressMode &AM, SDOperand &Base,
SDOperand &Scale, SDOperand &Index,
SDOperand &Disp) {
Base = (AM.BaseType == X86ISelAddressMode::FrameIndexBase) ?
CurDAG->getTargetFrameIndex(AM.Base.FrameIndex, MVT::i32) : AM.Base.Reg;
Scale = getI8Imm(AM.Scale);
Index = AM.IndexReg;
Disp = AM.GV ? CurDAG->getTargetGlobalAddress(AM.GV, MVT::i32, AM.Disp)
: (AM.CP ?
CurDAG->getTargetConstantPool(AM.CP, MVT::i32, AM.Align, AM.Disp)
: getI32Imm(AM.Disp));
}
/// getI8Imm - Return a target constant with the specified value, of type
/// i8.
inline SDOperand getI8Imm(unsigned Imm) {
return CurDAG->getTargetConstant(Imm, MVT::i8);
}
/// getI16Imm - Return a target constant with the specified value, of type
/// i16.
inline SDOperand getI16Imm(unsigned Imm) {
return CurDAG->getTargetConstant(Imm, MVT::i16);
}
/// getI32Imm - Return a target constant with the specified value, of type
/// i32.
inline SDOperand getI32Imm(unsigned Imm) {
return CurDAG->getTargetConstant(Imm, MVT::i32);
}
/// getGlobalBaseReg - insert code into the entry mbb to materialize the PIC
/// base register. Return the virtual register that holds this value.
SDOperand getGlobalBaseReg();
/// DAGSize - Number of nodes in the DAG.
///
unsigned DAGSize;
/// TopOrder - Topological ordering of all nodes in the DAG.
///
SDNode* *TopOrder;
/// IdToOrder - Node id to topological order map.
///
unsigned *IdToOrder;
/// RMRange - The range of reachibility information available for the
/// particular source node.
unsigned *RMRange;
/// ReachibilityMatrix - A N x N matrix representing all pairs reachibility
/// information. One bit per potential edge.
unsigned char *ReachibilityMatrix;
inline void setReachable(SDNode *f, SDNode *t) {
unsigned Idx = f->getNodeId() * DAGSize + t->getNodeId();
ReachibilityMatrix[Idx / 8] |= 1 << (Idx % 8);
}
inline bool isReachable(SDNode *f, SDNode *t) {
unsigned Idx = f->getNodeId() * DAGSize + t->getNodeId();
return ReachibilityMatrix[Idx / 8] & (1 << (Idx % 8));
}
#ifndef NDEBUG
unsigned Indent;
#endif
};
}
bool X86DAGToDAGISel::IsFoldableBy(SDNode *N, SDNode *U) {
// If U use can somehow reach N through another path then U can't fold N or
// it will create a cycle. e.g. In the following diagram, U can reach N
// through X. If N is foled into into U, then X is both a predecessor and
// a successor of U.
//
// [ N ]
// ^ ^
// | |
// / \---
// / [X]
// | ^
// [U]--------|
DeterminReachibility(U, N);
assert(isReachable(U, N) && "Attempting to fold a non-operand node?");
for (SDNode::op_iterator I = U->op_begin(), E = U->op_end(); I != E; ++I) {
SDNode *P = I->Val;
if (P != N && isReachable(P, N))
return false;
}
return true;
}
/// DetermineTopologicalOrdering - Determine topological ordering of the nodes
/// in the DAG.
void X86DAGToDAGISel::DetermineTopologicalOrdering() {
DAGSize = CurDAG->AssignNodeIds();
TopOrder = new SDNode*[DAGSize];
IdToOrder = new unsigned[DAGSize];
memset(IdToOrder, 0, DAGSize * sizeof(unsigned));
RMRange = new unsigned[DAGSize];
memset(RMRange, 0, DAGSize * sizeof(unsigned));
std::vector<unsigned> InDegree(DAGSize);
std::list<SDNode*> Sources;
for (SelectionDAG::allnodes_iterator I = CurDAG->allnodes_begin(),
E = CurDAG->allnodes_end(); I != E; ++I) {
SDNode *N = I;
unsigned Degree = N->use_size();
InDegree[N->getNodeId()] = Degree;
if (Degree == 0)
Sources.push_back(I);
}
unsigned Order = 0;
while (!Sources.empty()) {
SDNode *N = Sources.front();
Sources.pop_front();
TopOrder[Order] = N;
IdToOrder[N->getNodeId()] = Order;
Order++;
for (SDNode::op_iterator I = N->op_begin(), E = N->op_end(); I != E; ++I) {
SDNode *P = I->Val;
int PId = P->getNodeId();
unsigned Degree = InDegree[PId] - 1;
if (Degree == 0)
Sources.push_back(P);
InDegree[PId] = Degree;
}
}
}
void X86DAGToDAGISel::DeterminReachibility(SDNode *f, SDNode *t) {
if (!ReachibilityMatrix) {
DetermineTopologicalOrdering();
unsigned RMSize = DAGSize * DAGSize / 8;
if ((DAGSize * DAGSize) % 8)
RMSize++;
ReachibilityMatrix = new unsigned char[RMSize];
memset(ReachibilityMatrix, 0, RMSize);
}
int Idf = f->getNodeId();
int Idt = t->getNodeId();
unsigned Orderf = IdToOrder[Idf];
unsigned Ordert = IdToOrder[Idt];
unsigned Range = RMRange[Idf];
if (Range >= Ordert)
return;
if (Range < Orderf)
Range = Orderf;
for (unsigned i = Range; i < Ordert; ++i) {
SDNode *N = TopOrder[i];
setReachable(N, N);
// If N is a leaf node, there is nothing more to do.
if (N->getNumOperands() == 0)
continue;
for (unsigned i2 = Orderf; ; ++i2) {
SDNode *M = TopOrder[i2];
if (isReachable(M, N)) {
// Update reachibility from M to N's operands.
for (SDNode::op_iterator I = N->op_begin(), E = N->op_end(); I != E;++I)
setReachable(M, I->Val);
}
if (M == N) break;
}
}
RMRange[Idf] = Ordert;
}
/// InstructionSelectBasicBlock - This callback is invoked by SelectionDAGISel
/// when it has created a SelectionDAG for us to codegen.
void X86DAGToDAGISel::InstructionSelectBasicBlock(SelectionDAG &DAG) {
DEBUG(BB->dump());
MachineFunction::iterator FirstMBB = BB;
// Codegen the basic block.
#ifndef NDEBUG
DEBUG(std::cerr << "===== Instruction selection begins:\n");
Indent = 0;
#endif
DAG.setRoot(SelectRoot(DAG.getRoot()));
assert(InFlightSet.empty() && "ISel InFlightSet has not been emptied!");
#ifndef NDEBUG
DEBUG(std::cerr << "===== Instruction selection ends:\n");
#endif
if (ReachibilityMatrix) {
delete[] ReachibilityMatrix;
delete[] TopOrder;
delete[] IdToOrder;
delete[] RMRange;
ReachibilityMatrix = NULL;
TopOrder = NULL;
IdToOrder = RMRange = NULL;
}
CodeGenMap.clear();
HandleMap.clear();
ReplaceMap.clear();
DAG.RemoveDeadNodes();
// Emit machine code to BB.
ScheduleAndEmitDAG(DAG);
// If we are emitting FP stack code, scan the basic block to determine if this
// block defines any FP values. If so, put an FP_REG_KILL instruction before
// the terminator of the block.
if (!Subtarget->hasSSE2()) {
// Note that FP stack instructions *are* used in SSE code when returning
// values, but these are not live out of the basic block, so we don't need
// an FP_REG_KILL in this case either.
bool ContainsFPCode = false;
// Scan all of the machine instructions in these MBBs, checking for FP
// stores.
MachineFunction::iterator MBBI = FirstMBB;
do {
for (MachineBasicBlock::iterator I = MBBI->begin(), E = MBBI->end();
!ContainsFPCode && I != E; ++I) {
for (unsigned op = 0, e = I->getNumOperands(); op != e; ++op) {
if (I->getOperand(op).isRegister() && I->getOperand(op).isDef() &&
MRegisterInfo::isVirtualRegister(I->getOperand(op).getReg()) &&
RegMap->getRegClass(I->getOperand(0).getReg()) ==
X86::RFPRegisterClass) {
ContainsFPCode = true;
break;
}
}
}
} while (!ContainsFPCode && &*(MBBI++) != BB);
// Check PHI nodes in successor blocks. These PHI's will be lowered to have
// a copy of the input value in this block.
if (!ContainsFPCode) {
// Final check, check LLVM BB's that are successors to the LLVM BB
// corresponding to BB for FP PHI nodes.
const BasicBlock *LLVMBB = BB->getBasicBlock();
const PHINode *PN;
for (succ_const_iterator SI = succ_begin(LLVMBB), E = succ_end(LLVMBB);
!ContainsFPCode && SI != E; ++SI) {
for (BasicBlock::const_iterator II = SI->begin();
(PN = dyn_cast<PHINode>(II)); ++II) {
if (PN->getType()->isFloatingPoint()) {
ContainsFPCode = true;
break;
}
}
}
}
// Finally, if we found any FP code, emit the FP_REG_KILL instruction.
if (ContainsFPCode) {
BuildMI(*BB, BB->getFirstTerminator(), X86::FP_REG_KILL, 0);
++NumFPKill;
}
}
}
/// EmitSpecialCodeForMain - Emit any code that needs to be executed only in
/// the main function.
void X86DAGToDAGISel::EmitSpecialCodeForMain(MachineBasicBlock *BB,
MachineFrameInfo *MFI) {
if (Subtarget->TargetType == X86Subtarget::isCygwin)
BuildMI(BB, X86::CALLpcrel32, 1).addExternalSymbol("__main");
// Switch the FPU to 64-bit precision mode for better compatibility and speed.
int CWFrameIdx = MFI->CreateStackObject(2, 2);
addFrameReference(BuildMI(BB, X86::FNSTCW16m, 4), CWFrameIdx);
// Set the high part to be 64-bit precision.
addFrameReference(BuildMI(BB, X86::MOV8mi, 5),
CWFrameIdx, 1).addImm(2);
// Reload the modified control word now.
addFrameReference(BuildMI(BB, X86::FLDCW16m, 4), CWFrameIdx);
}
void X86DAGToDAGISel::EmitFunctionEntryCode(Function &Fn, MachineFunction &MF) {
// If this is main, emit special code for main.
MachineBasicBlock *BB = MF.begin();
if (Fn.hasExternalLinkage() && Fn.getName() == "main")
EmitSpecialCodeForMain(BB, MF.getFrameInfo());
}
/// 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(SDOperand N, X86ISelAddressMode &AM,
bool isRoot) {
bool Available = false;
// If N has already been selected, reuse the result unless in some very
// specific cases.
std::map<SDOperand, SDOperand>::iterator CGMI= CodeGenMap.find(N.getValue(0));
if (CGMI != CodeGenMap.end()) {
Available = true;
}
switch (N.getOpcode()) {
default: break;
case ISD::Constant:
AM.Disp += cast<ConstantSDNode>(N)->getValue();
return false;
case X86ISD::Wrapper:
// If both base and index components have been picked, we can't fit
// the result available in the register in the addressing mode. Duplicate
// GlobalAddress or ConstantPool as displacement.
if (!Available || (AM.Base.Reg.Val && AM.IndexReg.Val)) {
if (ConstantPoolSDNode *CP =
dyn_cast<ConstantPoolSDNode>(N.getOperand(0))) {
if (AM.CP == 0) {
AM.CP = CP->get();
AM.Align = CP->getAlignment();
AM.Disp += CP->getOffset();
return false;
}
} else if (GlobalAddressSDNode *G =
dyn_cast<GlobalAddressSDNode>(N.getOperand(0))) {
if (AM.GV == 0) {
AM.GV = G->getGlobal();
AM.Disp += G->getOffset();
return false;
}
}
}
break;
case ISD::FrameIndex:
if (AM.BaseType == X86ISelAddressMode::RegBase && AM.Base.Reg.Val == 0) {
AM.BaseType = X86ISelAddressMode::FrameIndexBase;
AM.Base.FrameIndex = cast<FrameIndexSDNode>(N)->getIndex();
return false;
}
break;
case ISD::SHL:
if (!Available && AM.IndexReg.Val == 0 && AM.Scale == 1)
if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N.Val->getOperand(1))) {
unsigned Val = CN->getValue();
if (Val == 1 || Val == 2 || Val == 3) {
AM.Scale = 1 << Val;
SDOperand ShVal = N.Val->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 (ShVal.Val->getOpcode() == ISD::ADD && ShVal.hasOneUse() &&
isa<ConstantSDNode>(ShVal.Val->getOperand(1))) {
AM.IndexReg = ShVal.Val->getOperand(0);
ConstantSDNode *AddVal =
cast<ConstantSDNode>(ShVal.Val->getOperand(1));
AM.Disp += AddVal->getValue() << Val;
} else {
AM.IndexReg = ShVal;
}
return false;
}
}
break;
case ISD::MUL:
// X*[3,5,9] -> X+X*[2,4,8]
if (!Available &&
AM.BaseType == X86ISelAddressMode::RegBase &&
AM.Base.Reg.Val == 0 &&
AM.IndexReg.Val == 0)
if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N.Val->getOperand(1)))
if (CN->getValue() == 3 || CN->getValue() == 5 || CN->getValue() == 9) {
AM.Scale = unsigned(CN->getValue())-1;
SDOperand MulVal = N.Val->getOperand(0);
SDOperand 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.Val->getOpcode() == ISD::ADD && MulVal.hasOneUse() &&
isa<ConstantSDNode>(MulVal.Val->getOperand(1))) {
Reg = MulVal.Val->getOperand(0);
ConstantSDNode *AddVal =
cast<ConstantSDNode>(MulVal.Val->getOperand(1));
AM.Disp += AddVal->getValue() * CN->getValue();
} else {
Reg = N.Val->getOperand(0);
}
AM.IndexReg = AM.Base.Reg = Reg;
return false;
}
break;
case ISD::ADD: {
if (!Available) {
X86ISelAddressMode Backup = AM;
if (!MatchAddress(N.Val->getOperand(0), AM, false) &&
!MatchAddress(N.Val->getOperand(1), AM, false))
return false;
AM = Backup;
if (!MatchAddress(N.Val->getOperand(1), AM, false) &&
!MatchAddress(N.Val->getOperand(0), AM, false))
return false;
AM = Backup;
}
break;
}
case ISD::OR: {
if (!Available) {
X86ISelAddressMode Backup = AM;
// Look for (x << c1) | c2 where (c2 < c1)
ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N.Val->getOperand(0));
if (CN && !MatchAddress(N.Val->getOperand(1), AM, false)) {
if (AM.GV == NULL && AM.Disp == 0 && CN->getValue() < AM.Scale) {
AM.Disp = CN->getValue();
return false;
}
}
AM = Backup;
CN = dyn_cast<ConstantSDNode>(N.Val->getOperand(1));
if (CN && !MatchAddress(N.Val->getOperand(0), AM, false)) {
if (AM.GV == NULL && AM.Disp == 0 && CN->getValue() < AM.Scale) {
AM.Disp = CN->getValue();
return false;
}
}
AM = Backup;
}
break;
}
}
// Is the base register already occupied?
if (AM.BaseType != X86ISelAddressMode::RegBase || AM.Base.Reg.Val) {
// If so, check to see if the scale index register is set.
if (AM.IndexReg.Val == 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.
bool X86DAGToDAGISel::SelectAddr(SDOperand N, SDOperand &Base, SDOperand &Scale,
SDOperand &Index, SDOperand &Disp) {
X86ISelAddressMode AM;
if (MatchAddress(N, AM))
return false;
if (AM.BaseType == X86ISelAddressMode::RegBase) {
if (!AM.Base.Reg.Val)
AM.Base.Reg = CurDAG->getRegister(0, MVT::i32);
}
if (!AM.IndexReg.Val)
AM.IndexReg = CurDAG->getRegister(0, MVT::i32);
getAddressOperands(AM, Base, Scale, Index, Disp);
return true;
}
/// 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(SDOperand N, SDOperand &Base,
SDOperand &Scale,
SDOperand &Index, SDOperand &Disp) {
X86ISelAddressMode AM;
if (MatchAddress(N, AM))
return false;
unsigned Complexity = 0;
if (AM.BaseType == X86ISelAddressMode::RegBase)
if (AM.Base.Reg.Val)
Complexity = 1;
else
AM.Base.Reg = CurDAG->getRegister(0, MVT::i32);
else if (AM.BaseType == X86ISelAddressMode::FrameIndexBase)
Complexity = 4;
if (AM.IndexReg.Val)
Complexity++;
else
AM.IndexReg = CurDAG->getRegister(0, MVT::i32);
if (AM.Scale > 2)
Complexity += 2;
// Don't match just leal(,%reg,2). It's cheaper to do addl %reg, %reg
else 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.GV || AM.CP)
Complexity += 2;
if (AM.Disp && (AM.Base.Reg.Val || AM.IndexReg.Val))
Complexity++;
if (Complexity > 2) {
getAddressOperands(AM, Base, Scale, Index, Disp);
return true;
}
return false;
}
bool X86DAGToDAGISel::TryFoldLoad(SDOperand P, SDOperand N,
SDOperand &Base, SDOperand &Scale,
SDOperand &Index, SDOperand &Disp) {
if (N.getOpcode() == ISD::LOAD &&
N.hasOneUse() &&
!CodeGenMap.count(N.getValue(0)) &&
!IsFoldableBy(N.Val, P.Val))
return SelectAddr(N.getOperand(1), Base, Scale, Index, Disp);
return false;
}
static bool isRegister0(SDOperand Op) {
if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(Op))
return (R->getReg() == 0);
return false;
}
/// getGlobalBaseReg - Output the instructions required to put the
/// base address to use for accessing globals into a register.
///
SDOperand X86DAGToDAGISel::getGlobalBaseReg() {
if (!GlobalBaseReg) {
// Insert the set of GlobalBaseReg into the first MBB of the function
MachineBasicBlock &FirstMBB = BB->getParent()->front();
MachineBasicBlock::iterator MBBI = FirstMBB.begin();
SSARegMap *RegMap = BB->getParent()->getSSARegMap();
// FIXME: when we get to LP64, we will need to create the appropriate
// type of register here.
GlobalBaseReg = RegMap->createVirtualRegister(X86::GR32RegisterClass);
BuildMI(FirstMBB, MBBI, X86::MovePCtoStack, 0);
BuildMI(FirstMBB, MBBI, X86::POP32r, 1, GlobalBaseReg);
}
return CurDAG->getRegister(GlobalBaseReg, MVT::i32);
}
static SDNode *FindCallStartFromCall(SDNode *Node) {
if (Node->getOpcode() == ISD::CALLSEQ_START) return Node;
assert(Node->getOperand(0).getValueType() == MVT::Other &&
"Node doesn't have a token chain argument!");
return FindCallStartFromCall(Node->getOperand(0).Val);
}
void X86DAGToDAGISel::Select(SDOperand &Result, SDOperand N) {
SDNode *Node = N.Val;
MVT::ValueType NVT = Node->getValueType(0);
unsigned Opc, MOpc;
unsigned Opcode = Node->getOpcode();
#ifndef NDEBUG
DEBUG(std::cerr << std::string(Indent, ' '));
DEBUG(std::cerr << "Selecting: ");
DEBUG(Node->dump(CurDAG));
DEBUG(std::cerr << "\n");
Indent += 2;
#endif
if (Opcode >= ISD::BUILTIN_OP_END && Opcode < X86ISD::FIRST_NUMBER) {
Result = N;
#ifndef NDEBUG
DEBUG(std::cerr << std::string(Indent-2, ' '));
DEBUG(std::cerr << "== ");
DEBUG(Node->dump(CurDAG));
DEBUG(std::cerr << "\n");
Indent -= 2;
#endif
return; // Already selected.
}
std::map<SDOperand, SDOperand>::iterator CGMI = CodeGenMap.find(N);
if (CGMI != CodeGenMap.end()) {
Result = CGMI->second;
#ifndef NDEBUG
DEBUG(std::cerr << std::string(Indent-2, ' '));
DEBUG(std::cerr << "== ");
DEBUG(Result.Val->dump(CurDAG));
DEBUG(std::cerr << "\n");
Indent -= 2;
#endif
return;
}
switch (Opcode) {
default: break;
case X86ISD::GlobalBaseReg:
Result = getGlobalBaseReg();
return;
case ISD::ADD: {
// Turn ADD X, c to MOV32ri X+c. This cannot be done with tblgen'd
// code and is matched first so to prevent it from being turned into
// LEA32r X+c.
SDOperand N0 = N.getOperand(0);
SDOperand N1 = N.getOperand(1);
if (N.Val->getValueType(0) == MVT::i32 &&
N0.getOpcode() == X86ISD::Wrapper &&
N1.getOpcode() == ISD::Constant) {
unsigned Offset = (unsigned)cast<ConstantSDNode>(N1)->getValue();
SDOperand C(0, 0);
// TODO: handle ExternalSymbolSDNode.
if (GlobalAddressSDNode *G =
dyn_cast<GlobalAddressSDNode>(N0.getOperand(0))) {
C = CurDAG->getTargetGlobalAddress(G->getGlobal(), MVT::i32,
G->getOffset() + Offset);
} else if (ConstantPoolSDNode *CP =
dyn_cast<ConstantPoolSDNode>(N0.getOperand(0))) {
C = CurDAG->getTargetConstantPool(CP->get(), MVT::i32,
CP->getAlignment(),
CP->getOffset()+Offset);
}
if (C.Val) {
if (N.Val->hasOneUse()) {
Result = CurDAG->SelectNodeTo(N.Val, X86::MOV32ri, MVT::i32, C);
} else {
SDNode *ResNode = CurDAG->getTargetNode(X86::MOV32ri, MVT::i32, C);
Result = CodeGenMap[N] = SDOperand(ResNode, 0);
}
return;
}
}
// Other cases are handled by auto-generated code.
break;
}
case ISD::MULHU:
case ISD::MULHS: {
if (Opcode == ISD::MULHU)
switch (NVT) {
default: assert(0 && "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;
}
else
switch (NVT) {
default: assert(0 && "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;
}
unsigned LoReg, HiReg;
switch (NVT) {
default: assert(0 && "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;
}
SDOperand N0 = Node->getOperand(0);
SDOperand N1 = Node->getOperand(1);
bool foldedLoad = false;
SDOperand Tmp0, Tmp1, Tmp2, Tmp3;
foldedLoad = TryFoldLoad(N, N1, Tmp0, Tmp1, Tmp2, Tmp3);
// MULHU and MULHS are commmutative
if (!foldedLoad) {
foldedLoad = TryFoldLoad(N, N0, Tmp0, Tmp1, Tmp2, Tmp3);
if (foldedLoad) {
N0 = Node->getOperand(1);
N1 = Node->getOperand(0);
}
}
SDOperand Chain;
if (foldedLoad)
Select(Chain, N1.getOperand(0));
else
Chain = CurDAG->getEntryNode();
SDOperand InFlag(0, 0);
Select(N0, N0);
Chain = CurDAG->getCopyToReg(Chain, CurDAG->getRegister(LoReg, NVT),
N0, InFlag);
InFlag = Chain.getValue(1);
if (foldedLoad) {
Select(Tmp0, Tmp0);
Select(Tmp1, Tmp1);
Select(Tmp2, Tmp2);
Select(Tmp3, Tmp3);
SDNode *CNode =
CurDAG->getTargetNode(MOpc, MVT::Other, MVT::Flag, Tmp0, Tmp1,
Tmp2, Tmp3, Chain, InFlag);
Chain = SDOperand(CNode, 0);
InFlag = SDOperand(CNode, 1);
} else {
Select(N1, N1);
InFlag =
SDOperand(CurDAG->getTargetNode(Opc, MVT::Flag, N1, InFlag), 0);
}
Result = CurDAG->getCopyFromReg(Chain, HiReg, NVT, InFlag);
CodeGenMap[N.getValue(0)] = Result;
if (foldedLoad) {
CodeGenMap[N1.getValue(1)] = Result.getValue(1);
AddHandleReplacement(N1.Val, 1, Result.Val, 1);
}
#ifndef NDEBUG
DEBUG(std::cerr << std::string(Indent-2, ' '));
DEBUG(std::cerr << "== ");
DEBUG(Result.Val->dump(CurDAG));
DEBUG(std::cerr << "\n");
Indent -= 2;
#endif
return;
}
case ISD::SDIV:
case ISD::UDIV:
case ISD::SREM:
case ISD::UREM: {
bool isSigned = Opcode == ISD::SDIV || Opcode == ISD::SREM;
bool isDiv = Opcode == ISD::SDIV || Opcode == ISD::UDIV;
if (!isSigned)
switch (NVT) {
default: assert(0 && "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;
}
else
switch (NVT) {
default: assert(0 && "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;
}
unsigned LoReg, HiReg;
unsigned ClrOpcode, SExtOpcode;
switch (NVT) {
default: assert(0 && "Unsupported VT!");
case MVT::i8:
LoReg = X86::AL; HiReg = X86::AH;
ClrOpcode = X86::MOV8r0;
SExtOpcode = X86::CBW;
break;
case MVT::i16:
LoReg = X86::AX; HiReg = X86::DX;
ClrOpcode = X86::MOV16r0;
SExtOpcode = X86::CWD;
break;
case MVT::i32:
LoReg = X86::EAX; HiReg = X86::EDX;
ClrOpcode = X86::MOV32r0;
SExtOpcode = X86::CDQ;
break;
}
SDOperand N0 = Node->getOperand(0);
SDOperand N1 = Node->getOperand(1);
bool foldedLoad = false;
SDOperand Tmp0, Tmp1, Tmp2, Tmp3;
foldedLoad = TryFoldLoad(N, N1, Tmp0, Tmp1, Tmp2, Tmp3);
SDOperand Chain;
if (foldedLoad)
Select(Chain, N1.getOperand(0));
else
Chain = CurDAG->getEntryNode();
SDOperand InFlag(0, 0);
Select(N0, N0);
Chain = CurDAG->getCopyToReg(Chain, CurDAG->getRegister(LoReg, NVT),
N0, InFlag);
InFlag = Chain.getValue(1);
if (isSigned) {
// Sign extend the low part into the high part.
InFlag =
SDOperand(CurDAG->getTargetNode(SExtOpcode, MVT::Flag, InFlag), 0);
} else {
// Zero out the high part, effectively zero extending the input.
SDOperand ClrNode = SDOperand(CurDAG->getTargetNode(ClrOpcode, NVT), 0);
Chain = CurDAG->getCopyToReg(Chain, CurDAG->getRegister(HiReg, NVT),
ClrNode, InFlag);
InFlag = Chain.getValue(1);
}
if (foldedLoad) {
Select(Tmp0, Tmp0);
Select(Tmp1, Tmp1);
Select(Tmp2, Tmp2);
Select(Tmp3, Tmp3);
SDNode *CNode =
CurDAG->getTargetNode(MOpc, MVT::Other, MVT::Flag, Tmp0, Tmp1,
Tmp2, Tmp3, Chain, InFlag);
Chain = SDOperand(CNode, 0);
InFlag = SDOperand(CNode, 1);
} else {
Select(N1, N1);
InFlag =
SDOperand(CurDAG->getTargetNode(Opc, MVT::Flag, N1, InFlag), 0);
}
Result = CurDAG->getCopyFromReg(Chain, isDiv ? LoReg : HiReg,
NVT, InFlag);
CodeGenMap[N.getValue(0)] = Result;
if (foldedLoad) {
CodeGenMap[N1.getValue(1)] = Result.getValue(1);
AddHandleReplacement(N1.Val, 1, Result.Val, 1);
}
#ifndef NDEBUG
DEBUG(std::cerr << std::string(Indent-2, ' '));
DEBUG(std::cerr << "== ");
DEBUG(Result.Val->dump(CurDAG));
DEBUG(std::cerr << "\n");
Indent -= 2;
#endif
return;
}
case ISD::TRUNCATE: {
if (NVT == MVT::i8) {
unsigned Opc2;
MVT::ValueType VT;
switch (Node->getOperand(0).getValueType()) {
default: assert(0 && "Unknown truncate!");
case MVT::i16:
Opc = X86::MOV16to16_;
VT = MVT::i16;
Opc2 = X86::TRUNC_GR16_GR8;
break;
case MVT::i32:
Opc = X86::MOV32to32_;
VT = MVT::i32;
Opc2 = X86::TRUNC_GR32_GR8;
break;
}
SDOperand Tmp0, Tmp1;
Select(Tmp0, Node->getOperand(0));
Tmp1 = SDOperand(CurDAG->getTargetNode(Opc, VT, Tmp0), 0);
Result = CodeGenMap[N] =
SDOperand(CurDAG->getTargetNode(Opc2, NVT, Tmp1), 0);
#ifndef NDEBUG
DEBUG(std::cerr << std::string(Indent-2, ' '));
DEBUG(std::cerr << "== ");
DEBUG(Result.Val->dump(CurDAG));
DEBUG(std::cerr << "\n");
Indent -= 2;
#endif
return;
}
break;
}
}
SelectCode(Result, N);
#ifndef NDEBUG
DEBUG(std::cerr << std::string(Indent-2, ' '));
DEBUG(std::cerr << "=> ");
DEBUG(Result.Val->dump(CurDAG));
DEBUG(std::cerr << "\n");
Indent -= 2;
#endif
}
bool X86DAGToDAGISel::
SelectInlineAsmMemoryOperand(const SDOperand &Op, char ConstraintCode,
std::vector<SDOperand> &OutOps, SelectionDAG &DAG){
SDOperand Op0, Op1, Op2, Op3;
switch (ConstraintCode) {
case 'o': // offsetable ??
case 'v': // not offsetable ??
default: return true;
case 'm': // memory
if (!SelectAddr(Op, Op0, Op1, Op2, Op3))
return true;
break;
}
OutOps.resize(4);
Select(OutOps[0], Op0);
Select(OutOps[1], Op1);
Select(OutOps[2], Op2);
Select(OutOps[3], Op3);
return false;
}
/// createX86ISelDag - This pass converts a legalized DAG into a
/// X86-specific DAG, ready for instruction scheduling.
///
FunctionPass *llvm::createX86ISelDag(X86TargetMachine &TM) {
return new X86DAGToDAGISel(TM);
}
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