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Refactor isSafeToReMat out of 2addr pass.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55430 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng
2008-08-27 20:33:50 +00:00
parent 9d2968c824
commit df3b99381f
3 changed files with 28 additions and 29 deletions
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lib/CodeGen/TwoAddressInstructionPass.cpp
+1 -29
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@@ -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);