diff options
Diffstat (limited to 'llvm/lib/CodeGen/RegisterCoalescer.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/RegisterCoalescer.cpp | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/llvm/lib/CodeGen/RegisterCoalescer.cpp b/llvm/lib/CodeGen/RegisterCoalescer.cpp index 349fcde5ef7..ebac8f14bc1 100644 --- a/llvm/lib/CodeGen/RegisterCoalescer.cpp +++ b/llvm/lib/CodeGen/RegisterCoalescer.cpp @@ -494,6 +494,11 @@ bool RegisterCoalescer::hasOtherReachingDefs(LiveInterval &IntA, LiveInterval &IntB, VNInfo *AValNo, VNInfo *BValNo) { + // If AValNo has PHI kills, conservatively assume that IntB defs can reach + // the PHI values. + if (LIS->hasPHIKill(IntA, AValNo)) + return true; + for (LiveInterval::iterator AI = IntA.begin(), AE = IntA.end(); AI != AE; ++AI) { if (AI->valno != AValNo) continue; @@ -558,10 +563,7 @@ bool RegisterCoalescer::removeCopyByCommutingDef(const CoalescerPair &CP, // AValNo is the value number in A that defines the copy, A3 in the example. VNInfo *AValNo = IntA.getVNInfoAt(CopyIdx.getRegSlot(true)); assert(AValNo && "COPY source not live"); - - // If other defs can reach uses of this def, then it's not safe to perform - // the optimization. - if (AValNo->isPHIDef() || AValNo->isUnused() || AValNo->hasPHIKill()) + if (AValNo->isPHIDef() || AValNo->isUnused()) return false; MachineInstr *DefMI = LIS->getInstructionFromIndex(AValNo->def); if (!DefMI) |
