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Two fixes relating to debug value: 

* We should change the generated code because of a debug use.
* Avoid creating debug uses of undef, as they become a kill.
Test to follow.

llvm-svn: 133255
This commit is contained in:
Rafael Espindola 2011-06-17 13:59:43 +00:00
parent afdfed3d47
commit e0304d1df9
1 changed files with 10 additions and 0 deletions
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10
llvm/lib/CodeGen/TailDuplication.cpp
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@ -242,6 +242,14 @@ bool TailDuplicatePass::TailDuplicateBlocks(MachineFunction &MF) {
MachineOperand &UseMO = UI.getOperand();
MachineInstr *UseMI = &*UI;
++UI;
if (UseMI->isDebugValue()) {
// SSAUpdate can replace the use with an undef. That creates
// a debug instruction that is a kill.
// FIXME: Should it SSAUpdate job to delete debug instructions
// instead of replacing the use with undef?
UseMI->eraseFromParent();
continue;
}
if (UseMI->getParent() == DefBB && !UseMI->isPHI())
continue;
SSAUpdate.RewriteUse(UseMO);
@ -283,6 +291,8 @@ static bool isDefLiveOut(unsigned Reg, MachineBasicBlock *BB,
for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(Reg),
UE = MRI->use_end(); UI != UE; ++UI) {
MachineInstr *UseMI = &*UI;
if (UseMI->isDebugValue())
continue;
if (UseMI->getParent() != BB)
return true;
}