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Teach MachineLICM and MachineSink how to clear kill flags conservatively

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when they move instructions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103737 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman
2010-05-13 20:34:42 +00:00
parent 1e5a6c46b8
commit e6cd757e68
4 changed files with 31 additions and 1 deletions
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lib/CodeGen/MachineLICM.cpp
+12 -1
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@@ -738,8 +738,10 @@ bool MachineLICM::EliminateCSE(MachineInstr *MI,
"Instructions with different phys regs are not identical!");
if (MO.isReg() && MO.isDef() &&
!TargetRegisterInfo::isPhysicalRegister(MO.getReg()))
!TargetRegisterInfo::isPhysicalRegister(MO.getReg())) {
RegInfo->replaceRegWith(MO.getReg(), Dup->getOperand(i).getReg());
RegInfo->clearKillFlags(Dup->getOperand(i).getReg());
}
}
MI->eraseFromParent();
++NumCSEed;
@@ -784,6 +786,15 @@ void MachineLICM::Hoist(MachineInstr *MI) {
// Otherwise, splice the instruction to the preheader.
CurPreheader->splice(CurPreheader->getFirstTerminator(),MI->getParent(),MI);
// Clear the kill flags of any register this instruction defines,
// since they may need to be live throughout the entire loop
// rather than just live for part of it.
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
if (MO.isReg() && MO.isDef() && !MO.isDead())
RegInfo->clearKillFlags(MO.getReg());
}
// Add to the CSE map.
if (CI != CSEMap.end())
CI->second.push_back(MI);