diff --git a/llvm/lib/CodeGen/TargetInstrInfo.cpp b/llvm/lib/CodeGen/TargetInstrInfo.cpp index 660a1a4d7ec47..518a9339d8d11 100644 --- a/llvm/lib/CodeGen/TargetInstrInfo.cpp +++ b/llvm/lib/CodeGen/TargetInstrInfo.cpp @@ -214,6 +214,24 @@ MachineInstr *TargetInstrInfo::commuteInstructionImpl(MachineInstr &MI, Reg1.isPhysical() ? MI.getOperand(Idx1).isRenamable() : false; bool Reg2IsRenamable = Reg2.isPhysical() ? MI.getOperand(Idx2).isRenamable() : false; + + // For a case like this: + // %0.sub = INST %0.sub(tied), %1.sub, implicit-def %0 + // we need to update the implicit-def after commuting to result in: + // %1.sub = INST %1.sub(tied), %0.sub, implicit-def %1 + SmallVector UpdateImplicitDefIdx; + if (HasDef && MI.hasImplicitDef()) { + const TargetRegisterInfo *TRI = + MI.getMF()->getSubtarget().getRegisterInfo(); + for (auto [OpNo, MO] : llvm::enumerate(MI.implicit_operands())) { + Register ImplReg = MO.getReg(); + if ((ImplReg.isVirtual() && ImplReg == Reg0) || + (ImplReg.isPhysical() && Reg0.isPhysical() && + TRI->isSubRegisterEq(ImplReg, Reg0))) + UpdateImplicitDefIdx.push_back(OpNo + MI.getNumExplicitOperands()); + } + } + // If destination is tied to either of the commuted source register, then // it must be updated. if (HasDef && Reg0 == Reg1 && @@ -238,15 +256,10 @@ MachineInstr *TargetInstrInfo::commuteInstructionImpl(MachineInstr &MI, } if (HasDef) { - // Use `substituteRegister` so that for a case like this: - // %0.sub = INST %0.sub(tied), %1.sub, implicit-def %0 - // the implicit-def is also updated, to result in: - // %1.sub = INST %1.sub(tied), %0.sub, implicit-def %1 - const TargetRegisterInfo &TRI = - *MI.getMF()->getSubtarget().getRegisterInfo(); - Register FromReg = CommutedMI->getOperand(0).getReg(); - CommutedMI->substituteRegister(FromReg, Reg0, /*SubRegIdx=*/0, TRI); + CommutedMI->getOperand(0).setReg(Reg0); CommutedMI->getOperand(0).setSubReg(SubReg0); + for (unsigned Idx : UpdateImplicitDefIdx) + CommutedMI->getOperand(Idx).setReg(Reg0); } CommutedMI->getOperand(Idx2).setReg(Reg1); CommutedMI->getOperand(Idx1).setReg(Reg2); diff --git a/llvm/test/CodeGen/X86/coalesce-commutative-implicit-def.mir b/llvm/test/CodeGen/X86/coalesce-commutative-implicit-def.mir index fe1235fe94f85..1f38430f631cc 100644 --- a/llvm/test/CodeGen/X86/coalesce-commutative-implicit-def.mir +++ b/llvm/test/CodeGen/X86/coalesce-commutative-implicit-def.mir @@ -35,3 +35,24 @@ body: | %0:gr64_with_sub_8bit = COPY %1:gr64_with_sub_8bit RET 0, implicit %0 ... +# Commuting instruction with 3 ops is handled correctly. +--- +name: commuting_3_ops +tracksRegLiveness: true +body: | + bb.0: + liveins: $ymm0, $ymm1 + + ; CHECK-LABEL: name: commuting_3_ops + ; CHECK: liveins: $ymm0, $ymm1 + ; CHECK-NEXT: {{ $}} + ; CHECK-NEXT: [[COPY:%[0-9]+]]:vr256 = COPY $ymm1 + ; CHECK-NEXT: [[COPY1:%[0-9]+]]:vr256 = COPY $ymm0 + ; CHECK-NEXT: [[COPY1:%[0-9]+]]:vr256 = contract nofpexcept VFMADD213PSYr [[COPY1]], [[COPY]], [[COPY]], implicit $mxcsr + ; CHECK-NEXT: RET 0, implicit [[COPY1]] + %0:vr256 = COPY $ymm1 + %1:vr256 = COPY $ymm0 + %0:vr256 = contract nofpexcept VFMADD231PSYr %0:vr256, %0:vr256, %1:vr256, implicit $mxcsr + %1:vr256 = COPY %0:vr256 + RET 0, implicit %1 +...