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Refactor isSafeToReMat out of 2addr pass. 

llvm-svn: 55430
This commit is contained in:
Evan Cheng 2008-08-27 20:33:50 +00:00
parent fdef44d7c4
commit 57dc078570
3 changed files with 28 additions and 29 deletions
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2
llvm/include/llvm/CodeGen/MachineInstr.h
View File

@ -250,6 +250,8 @@ public:
/// the instruction's location and its intended destination.
bool isSafeToMove(const TargetInstrInfo *TII, bool &SawStore);
bool isSafeToReMat(const TargetInstrInfo *TII, unsigned DstReg);
//
// Debugging support
//

25
llvm/lib/CodeGen/MachineInstr.cpp
View File

@ -711,6 +711,31 @@ bool MachineInstr::isSafeToMove(const TargetInstrInfo *TII, bool &SawStore) {
return true;
}
/// isSafeToReMat - Return true if it's safe to rematerialize the specified
/// instruction which defined the specified register instead of copying it.
bool MachineInstr::isSafeToReMat(const TargetInstrInfo *TII, unsigned DstReg) {
if (!TID->isAsCheapAsAMove())
return false;
bool SawStore = false;
if (!isSafeToMove(TII, SawStore))
return false;
for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
MachineOperand &MO = getOperand(i);
if (!MO.isRegister())
continue;
// FIXME: For now, do not remat any instruction with register operands.
// Later on, we can loosen the restriction is the register operands have
// not been modified between the def and use. Note, this is different from
// MachineSink because the code in no longer in two-address form (at least
// partially).
if (MO.isUse())
return false;
else if (!MO.isDead() && MO.getReg() != DstReg)
return false;
}
return true;
}
void MachineInstr::dump() const {
cerr << " " << *this;
}

30
llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
View File

@ -64,7 +64,6 @@ namespace {
unsigned Reg,
MachineBasicBlock::iterator OldPos);
bool isSafeToReMat(unsigned DstReg, MachineInstr *MI);
bool isProfitableToReMat(unsigned Reg, const TargetRegisterClass *RC,
MachineInstr *MI, MachineInstr *DefMI,
MachineBasicBlock *MBB, unsigned Loc,
@ -195,33 +194,6 @@ bool TwoAddressInstructionPass::Sink3AddrInstruction(MachineBasicBlock *MBB,
return true;
}
/// isSafeToReMat - Return true if it's safe to rematerialize the specified
/// instruction which defined the specified register instead of copying it.
bool
TwoAddressInstructionPass::isSafeToReMat(unsigned DstReg, MachineInstr *MI) {
const TargetInstrDesc &TID = MI->getDesc();
if (!TID.isAsCheapAsAMove())
return false;
bool SawStore = false;
if (!MI->isSafeToMove(TII, SawStore))
return false;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
if (!MO.isRegister())
continue;
// FIXME: For now, do not remat any instruction with register operands.
// Later on, we can loosen the restriction is the register operands have
// not been modified between the def and use. Note, this is different from
// MachineSink because the code in no longer in two-address form (at least
// partially).
if (MO.isUse())
return false;
else if (!MO.isDead() && MO.getReg() != DstReg)
return false;
}
return true;
}
/// isTwoAddrUse - Return true if the specified MI is using the specified
/// register as a two-address operand.
static bool isTwoAddrUse(MachineInstr *UseMI, unsigned Reg) {
@ -431,7 +403,7 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
// If it's safe and profitable, remat the definition instead of
// copying it.
if (DefMI &&
isSafeToReMat(regB, DefMI) &&
DefMI->isSafeToReMat(TII, regB) &&
isProfitableToReMat(regB, rc, mi, DefMI, mbbi, Dist,DistanceMap)){
DEBUG(cerr << "2addr: REMATTING : " << *DefMI << "\n");
TII->reMaterialize(*mbbi, mi, regA, DefMI);