diff options
| -rw-r--r-- | llvm/include/llvm/CodeGen/MachineInstr.h | 3 | ||||
| -rw-r--r-- | llvm/lib/CodeGen/MachineCSE.cpp | 11 | ||||
| -rw-r--r-- | llvm/lib/CodeGen/MachineInstr.cpp | 8 | ||||
| -rw-r--r-- | llvm/test/CodeGen/AArch64/arm64-cse.ll | 2 |
4 files changed, 21 insertions, 3 deletions
diff --git a/llvm/include/llvm/CodeGen/MachineInstr.h b/llvm/include/llvm/CodeGen/MachineInstr.h index 945ee0f5d73..d9bb555decc 100644 --- a/llvm/include/llvm/CodeGen/MachineInstr.h +++ b/llvm/include/llvm/CodeGen/MachineInstr.h @@ -1048,6 +1048,9 @@ public: bool addRegisterDead(unsigned Reg, const TargetRegisterInfo *RegInfo, bool AddIfNotFound = false); + /// Clear all dead flags on operands defining register @p Reg. + void clearRegisterDeads(unsigned Reg); + /// Mark all subregister defs of register @p Reg with the undef flag. /// This function is used when we determined to have a subregister def in an /// otherwise undefined super register. diff --git a/llvm/lib/CodeGen/MachineCSE.cpp b/llvm/lib/CodeGen/MachineCSE.cpp index 29604089ad8..21b9c5aa063 100644 --- a/llvm/lib/CodeGen/MachineCSE.cpp +++ b/llvm/lib/CodeGen/MachineCSE.cpp @@ -580,8 +580,15 @@ bool MachineCSE::ProcessBlock(MachineBasicBlock *MBB) { // Actually perform the elimination. if (DoCSE) { for (unsigned i = 0, e = CSEPairs.size(); i != e; ++i) { - MRI->replaceRegWith(CSEPairs[i].first, CSEPairs[i].second); - MRI->clearKillFlags(CSEPairs[i].second); + unsigned OldReg = CSEPairs[i].first; + unsigned NewReg = CSEPairs[i].second; + // OldReg may have been unused but is used now, clear the Dead flag + MachineInstr *Def = MRI->getUniqueVRegDef(NewReg); + assert(Def != nullptr && "CSEd register has no unique definition?"); + Def->clearRegisterDeads(NewReg); + // Replace with NewReg and clear kill flags which may be wrong now. + MRI->replaceRegWith(OldReg, NewReg); + MRI->clearKillFlags(NewReg); } // Go through implicit defs of CSMI and MI, if a def is not dead at MI, diff --git a/llvm/lib/CodeGen/MachineInstr.cpp b/llvm/lib/CodeGen/MachineInstr.cpp index 470d6cbdb05..f863bb8197e 100644 --- a/llvm/lib/CodeGen/MachineInstr.cpp +++ b/llvm/lib/CodeGen/MachineInstr.cpp @@ -1889,6 +1889,14 @@ bool MachineInstr::addRegisterDead(unsigned Reg, return true; } +void MachineInstr::clearRegisterDeads(unsigned Reg) { + for (MachineOperand &MO : operands()) { + if (!MO.isReg() || !MO.isDef() || MO.getReg() != Reg) + continue; + MO.setIsDead(false); + } +} + void MachineInstr::addRegisterDefReadUndef(unsigned Reg) { for (MachineOperand &MO : operands()) { if (!MO.isReg() || !MO.isDef() || MO.getReg() != Reg || MO.getSubReg() == 0) diff --git a/llvm/test/CodeGen/AArch64/arm64-cse.ll b/llvm/test/CodeGen/AArch64/arm64-cse.ll index b74ece8d288..508df7c27d0 100644 --- a/llvm/test/CodeGen/AArch64/arm64-cse.ll +++ b/llvm/test/CodeGen/AArch64/arm64-cse.ll @@ -1,4 +1,4 @@ -; RUN: llc -O3 < %s -aarch64-atomic-cfg-tidy=0 -aarch64-gep-opt=false | FileCheck %s +; RUN: llc -O3 < %s -aarch64-atomic-cfg-tidy=0 -aarch64-gep-opt=false -verify-machineinstrs | FileCheck %s target triple = "arm64-apple-ios" ; rdar://12462006 |
