diff --git a/llvm/lib/CodeGen/RegisterCoalescer.cpp b/llvm/lib/CodeGen/RegisterCoalescer.cpp index 57156cb61aa6..76edc08c52ad 100644 --- a/llvm/lib/CodeGen/RegisterCoalescer.cpp +++ b/llvm/lib/CodeGen/RegisterCoalescer.cpp @@ -1197,7 +1197,8 @@ static unsigned ComputeUltimateVN(VNInfo *VNI, // which allows us to coalesce A and B. // MI is the definition of B. LR is the life range of A that includes // the slot just before B. If we return true, we add "B = X" to DupCopies. -static bool RegistersDefinedFromSameValue(const TargetRegisterInfo &tri, +static bool RegistersDefinedFromSameValue(LiveIntervals &li, + const TargetRegisterInfo &tri, CoalescerPair &CP, MachineInstr *MI, LiveRange *LR, SmallVector &DupCopies) { @@ -1207,14 +1208,16 @@ static bool RegistersDefinedFromSameValue(const TargetRegisterInfo &tri, if (!MI->isFullCopy() || CP.isPartial() || CP.isPhys()) return false; - // FIXME: If "B = X" kills X, we have to move the kill back to its - // previous use. For now we just avoid the optimization in that case. - if (MI->getOperand(1).isKill()) - return false; - unsigned Dst = MI->getOperand(0).getReg(); unsigned Src = MI->getOperand(1).getReg(); + // FIXME: If "B = X" kills X, we have to move the kill back to its + // previous use. For now we just avoid the optimization in that case. + SlotIndex CopyIdx = li.getInstructionIndex(MI).getNextIndex().getDefIndex(); + LiveInterval &SrcInt = li.getInterval(Src); + if (SrcInt.killedAt(CopyIdx)) + return false; + if (!TargetRegisterInfo::isVirtualRegister(Src) || !TargetRegisterInfo::isVirtualRegister(Dst)) return false; @@ -1332,7 +1335,7 @@ bool RegisterCoalescer::JoinIntervals(CoalescerPair &CP) { // from the RHS interval, we can use its value #. MachineInstr *MI = VNI->getCopy(); if (!CP.isCoalescable(MI) && - !RegistersDefinedFromSameValue(*tri_, CP, MI, lr, DupCopies)) + !RegistersDefinedFromSameValue(*li_, *tri_, CP, MI, lr, DupCopies)) continue; LHSValsDefinedFromRHS[VNI] = lr->valno; @@ -1359,7 +1362,7 @@ bool RegisterCoalescer::JoinIntervals(CoalescerPair &CP) { // from the LHS interval, we can use its value #. MachineInstr *MI = VNI->getCopy(); if (!CP.isCoalescable(MI) && - !RegistersDefinedFromSameValue(*tri_, CP, MI, lr, DupCopies)) + !RegistersDefinedFromSameValue(*li_, *tri_, CP, MI, lr, DupCopies)) continue; RHSValsDefinedFromLHS[VNI] = lr->valno;