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* Cannot safely commute an instruction there are other defs which can reach its uses.

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* Ignore copy instructions which have already been coalesced.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47056 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng
2008-02-13 08:41:08 +00:00
parent 35327b3e57
commit e35a6d1dfb
1 changed files with 5 additions and 1 deletions
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6
lib/CodeGen/SimpleRegisterCoalescing.cpp
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@@ -237,7 +237,9 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA,
// AValNo is the value number in A that defines the copy, A3 in the example. // AValNo is the value number in A that defines the copy, A3 in the example.
LiveInterval::iterator ALR = IntA.FindLiveRangeContaining(CopyIdx-1); LiveInterval::iterator ALR = IntA.FindLiveRangeContaining(CopyIdx-1);
VNInfo *AValNo = ALR->valno; VNInfo *AValNo = ALR->valno;
if (AValNo->def == ~0U || AValNo->def == ~1U) // If other defs can reach uses of this def, then it's not safe to perform
// the optimization.
if (AValNo->def == ~0U || AValNo->def == ~1U || AValNo->hasPHIKill)
return false; return false;
MachineInstr *DefMI = li_->getInstructionFromIndex(AValNo->def); MachineInstr *DefMI = li_->getInstructionFromIndex(AValNo->def);
const TargetInstrDesc &TID = DefMI->getDesc(); const TargetInstrDesc &TID = DefMI->getDesc();
@@ -312,6 +314,8 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA,
MachineOperand &UseMO = UI.getOperand(); MachineOperand &UseMO = UI.getOperand();
++UI; ++UI;
MachineInstr *UseMI = UseMO.getParent(); MachineInstr *UseMI = UseMO.getParent();
if (JoinedCopies.count(UseMI))
continue;
unsigned UseIdx = li_->getInstructionIndex(UseMI); unsigned UseIdx = li_->getInstructionIndex(UseMI);
LiveInterval::iterator ULR = IntA.FindLiveRangeContaining(UseIdx); LiveInterval::iterator ULR = IntA.FindLiveRangeContaining(UseIdx);
if (ULR->valno != AValNo) if (ULR->valno != AValNo)