diff options
| author | Evan Cheng <evan.cheng@apple.com> | 2008-02-13 08:41:08 +0000 |
|---|---|---|
| committer | Evan Cheng <evan.cheng@apple.com> | 2008-02-13 08:41:08 +0000 |
| commit | e35a6d1dfb395925afe37bf0dc00fa2e006be190 (patch) | |
| tree | da142b553551f637fef4dad65a5775ae324169dd /lib/CodeGen | |
| parent | 35327b3e57f83f92325141e24fa5f0df6eb43b8c (diff) | |
* Cannot safely commute an instruction there are other defs which can reach its uses.
* 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
Diffstat (limited to 'lib/CodeGen')
| -rw-r--r-- | lib/CodeGen/SimpleRegisterCoalescing.cpp | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp index 94a94a1fe0..df5d3fa6f0 100644 --- a/lib/CodeGen/SimpleRegisterCoalescing.cpp +++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp @@ -237,7 +237,9 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA, // AValNo is the value number in A that defines the copy, A3 in the example. LiveInterval::iterator ALR = IntA.FindLiveRangeContaining(CopyIdx-1); 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; MachineInstr *DefMI = li_->getInstructionFromIndex(AValNo->def); const TargetInstrDesc &TID = DefMI->getDesc(); @@ -312,6 +314,8 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA, MachineOperand &UseMO = UI.getOperand(); ++UI; MachineInstr *UseMI = UseMO.getParent(); + if (JoinedCopies.count(UseMI)) + continue; unsigned UseIdx = li_->getInstructionIndex(UseMI); LiveInterval::iterator ULR = IntA.FindLiveRangeContaining(UseIdx); if (ULR->valno != AValNo) |