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Code refactoring. 

llvm-svn: 86085
This commit is contained in:
Evan Cheng 2009-11-05 00:51:13 +00:00
parent 209e31b883
commit 921152fe9d
1 changed files with 58 additions and 49 deletions
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107
llvm/lib/CodeGen/MachineLICM.cpp
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@ -111,6 +111,13 @@ namespace {
/// be hoistable.
MachineInstr *ExtractHoistableLoad(MachineInstr *MI);
/// EliminateCSE - Given a LICM'ed instruction, look for an instruction on
/// the preheader that compute the same value. If it's found, do a RAU on
/// with the definition of the existing instruction rather than hoisting
/// the instruction to the preheader.
bool EliminateCSE(MachineInstr *MI,
DenseMap<unsigned, std::vector<const MachineInstr*> >::iterator &CI);
/// Hoist - When an instruction is found to only use loop invariant operands
/// that is safe to hoist, this instruction is called to do the dirty work.
///
@ -349,37 +356,6 @@ bool MachineLICM::IsProfitableToHoist(MachineInstr &MI) {
return true;
}
static const MachineInstr *LookForDuplicate(const MachineInstr *MI,
std::vector<const MachineInstr*> &PrevMIs,
MachineRegisterInfo *RegInfo) {
unsigned NumOps = MI->getNumOperands();
for (unsigned i = 0, e = PrevMIs.size(); i != e; ++i) {
const MachineInstr *PrevMI = PrevMIs[i];
unsigned NumOps2 = PrevMI->getNumOperands();
if (NumOps != NumOps2)
continue;
bool IsSame = true;
for (unsigned j = 0; j != NumOps; ++j) {
const MachineOperand &MO = MI->getOperand(j);
if (MO.isReg() && MO.isDef()) {
if (RegInfo->getRegClass(MO.getReg()) !=
RegInfo->getRegClass(PrevMI->getOperand(j).getReg())) {
IsSame = false;
break;
}
continue;
}
if (!MO.isIdenticalTo(PrevMI->getOperand(j))) {
IsSame = false;
break;
}
}
if (IsSame)
return PrevMI;
}
return 0;
}
MachineInstr *MachineLICM::ExtractHoistableLoad(MachineInstr *MI) {
// If not, we may be able to unfold a load and hoist that.
// First test whether the instruction is loading from an amenable
@ -456,6 +432,55 @@ void MachineLICM::InitCSEMap(MachineBasicBlock *BB) {
}
}
static const MachineInstr *LookForDuplicate(const MachineInstr *MI,
std::vector<const MachineInstr*> &PrevMIs,
MachineRegisterInfo *RegInfo) {
unsigned NumOps = MI->getNumOperands();
for (unsigned i = 0, e = PrevMIs.size(); i != e; ++i) {
const MachineInstr *PrevMI = PrevMIs[i];
unsigned NumOps2 = PrevMI->getNumOperands();
if (NumOps != NumOps2)
continue;
bool IsSame = true;
for (unsigned j = 0; j != NumOps; ++j) {
const MachineOperand &MO = MI->getOperand(j);
if (MO.isReg() && MO.isDef()) {
if (RegInfo->getRegClass(MO.getReg()) !=
RegInfo->getRegClass(PrevMI->getOperand(j).getReg())) {
IsSame = false;
break;
}
continue;
}
if (!MO.isIdenticalTo(PrevMI->getOperand(j))) {
IsSame = false;
break;
}
}
if (IsSame)
return PrevMI;
}
return 0;
}
bool MachineLICM::EliminateCSE(MachineInstr *MI,
DenseMap<unsigned, std::vector<const MachineInstr*> >::iterator &CI) {
if (CI != CSEMap.end()) {
if (const MachineInstr *Dup = LookForDuplicate(MI, CI->second, RegInfo)) {
DEBUG(errs() << "CSEing " << *MI << " with " << *Dup);
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
if (MO.isReg() && MO.isDef())
RegInfo->replaceRegWith(MO.getReg(), Dup->getOperand(i).getReg());
}
MI->eraseFromParent();
++NumCSEed;
return true;
}
}
return false;
}
/// Hoist - When an instruction is found to use only loop invariant operands
/// that are safe to hoist, this instruction is called to do the dirty work.
///
@ -488,24 +513,8 @@ void MachineLICM::Hoist(MachineInstr *MI) {
unsigned Opcode = MI->getOpcode();
DenseMap<unsigned, std::vector<const MachineInstr*> >::iterator
CI = CSEMap.find(Opcode);
bool DoneCSE = false;
if (CI != CSEMap.end()) {
const MachineInstr *Dup = LookForDuplicate(MI, CI->second, RegInfo);
if (Dup) {
DEBUG(errs() << "CSEing " << *MI << " with " << *Dup);
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
if (MO.isReg() && MO.isDef())
RegInfo->replaceRegWith(MO.getReg(), Dup->getOperand(i).getReg());
}
MI->eraseFromParent();
DoneCSE = true;
++NumCSEed;
}
}
// Otherwise, splice the instruction to the preheader.
if (!DoneCSE) {
if (!EliminateCSE(MI, CI)) {
// Otherwise, splice the instruction to the preheader.
CurPreheader->splice(CurPreheader->getFirstTerminator(),MI->getParent(),MI);
// Add to the CSE map.