teach X86MCInstLower to lower the MOV32r0 and MOV8r0

pseudo instructions.

llvm-svn: 95433
This commit is contained in:
Chris Lattner 2010-02-05 21:21:06 +00:00
parent f77eadcfbb
commit 9b3cf069dc
2 changed files with 14 additions and 6 deletions

View File

@ -374,12 +374,20 @@ void X86MCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
case X86::MOVZX64rm8: LowerSubReg32_Op0(OutMI, X86::MOVZX32rm8); break;
case X86::MOVZX64rr16: LowerSubReg32_Op0(OutMI, X86::MOVZX32rr16); break;
case X86::MOVZX64rm16: LowerSubReg32_Op0(OutMI, X86::MOVZX32rm16); break;
case X86::MOV16r0: LowerSubReg32_Op0(OutMI, X86::MOV32r0); break;
case X86::MOV64r0: LowerSubReg32_Op0(OutMI, X86::MOV32r0); break;
case X86::SETB_C8r: LowerUnaryToTwoAddr(OutMI, X86::SBB8rr); break;
case X86::SETB_C16r: LowerUnaryToTwoAddr(OutMI, X86::SBB16rr); break;
case X86::SETB_C32r: LowerUnaryToTwoAddr(OutMI, X86::SBB32rr); break;
case X86::SETB_C64r: LowerUnaryToTwoAddr(OutMI, X86::SBB64rr); break;
case X86::MOV8r0: LowerUnaryToTwoAddr(OutMI, X86::XOR8rr); break;
case X86::MOV32r0: LowerUnaryToTwoAddr(OutMI, X86::XOR32rr); break;
case X86::MOV16r0:
LowerSubReg32_Op0(OutMI, X86::MOV32r0); // MOV16r0 -> MOV32r0
LowerUnaryToTwoAddr(OutMI, X86::XOR32rr); // MOV32r0 -> XOR32rr
break;
case X86::MOV64r0:
LowerSubReg32_Op0(OutMI, X86::MOV32r0); // MOV64r0 -> MOV32r0
LowerUnaryToTwoAddr(OutMI, X86::XOR32rr); // MOV32r0 -> XOR32rr
break;
}
}

View File

@ -3739,10 +3739,10 @@ let neverHasSideEffects = 1 in {
// Alias instructions that map movr0 to xor.
// FIXME: remove when we can teach regalloc that xor reg, reg is ok.
// FIXME: Set encoding to pseudo.
let Defs = [EFLAGS], isReMaterializable = 1, isAsCheapAsAMove = 1,
isCodeGenOnly = 1 in {
def MOV8r0 : I<0x30, MRMInitReg, (outs GR8 :$dst), (ins),
"xor{b}\t$dst, $dst",
def MOV8r0 : I<0x30, MRMInitReg, (outs GR8 :$dst), (ins), "",
[(set GR8:$dst, 0)]>;
// We want to rewrite MOV16r0 in terms of MOV32r0, because it's a smaller
@ -3754,8 +3754,8 @@ def MOV16r0 : I<0x31, MRMInitReg, (outs GR16:$dst), (ins),
"",
[(set GR16:$dst, 0)]>, OpSize;
def MOV32r0 : I<0x31, MRMInitReg, (outs GR32:$dst), (ins),
"xor{l}\t$dst, $dst",
// FIXME: Set encoding to pseudo.
def MOV32r0 : I<0x31, MRMInitReg, (outs GR32:$dst), (ins), "",
[(set GR32:$dst, 0)]>;
}