diff options
| -rw-r--r-- | llvm/lib/Target/X86/X86RegisterInfo.cpp | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/llvm/lib/Target/X86/X86RegisterInfo.cpp b/llvm/lib/Target/X86/X86RegisterInfo.cpp index 442b113c36c..774531e7a7b 100644 --- a/llvm/lib/Target/X86/X86RegisterInfo.cpp +++ b/llvm/lib/Target/X86/X86RegisterInfo.cpp @@ -265,9 +265,28 @@ void X86RegisterInfo::reMaterialize(MachineBasicBlock &MBB, MachineBasicBlock::iterator I, unsigned DestReg, const MachineInstr *Orig) const { - MachineInstr *MI = Orig->clone(); - MI->getOperand(0).setReg(DestReg); - MBB.insert(I, MI); + // MOV32r0 etc. are implemented with xor which clobbers condition code. + // Re-materialize them as movri instructions to avoid side effects. + switch (Orig->getOpcode()) { + case X86::MOV8r0: + BuildMI(MBB, I, TII.get(X86::MOV8ri), DestReg).addImm(0); + break; + case X86::MOV16r0: + BuildMI(MBB, I, TII.get(X86::MOV16ri), DestReg).addImm(0); + break; + case X86::MOV32r0: + BuildMI(MBB, I, TII.get(X86::MOV32ri), DestReg).addImm(0); + break; + case X86::MOV64r0: + BuildMI(MBB, I, TII.get(X86::MOV64ri32), DestReg).addImm(0); + break; + default: { + MachineInstr *MI = Orig->clone(); + MI->getOperand(0).setReg(DestReg); + MBB.insert(I, MI); + break; + } + } } static const MachineInstrBuilder &FuseInstrAddOperand(MachineInstrBuilder &MIB, |
