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factor some code better to avoid redundancy between

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isReallySideEffectFree and isReallyTriviallyReMaterializable.  Why is a load from
a global considered side-effect-free but not rematable?

llvm-svn: 45620
This commit is contained in:
Chris Lattner 2008-01-05 05:19:56 +00:00
parent 6ad8e32f6b
commit 86ca5928b5
1 changed files with 10 additions and 29 deletions
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39
lib/Target/X86/X86InstrInfo.cpp
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@ -135,11 +135,13 @@ bool X86InstrInfo::isReallyTriviallyReMaterializable(MachineInstr *MI) const {
case X86::MMX_MOVD64rm:
case X86::MMX_MOVQ64rm:
// Loads from constant pools are trivially rematerializable.
return MI->getOperand(1).isRegister() && MI->getOperand(2).isImmediate() &&
MI->getOperand(3).isRegister() && MI->getOperand(4).isConstantPoolIndex() &&
MI->getOperand(1).getReg() == 0 &&
MI->getOperand(2).getImm() == 1 &&
MI->getOperand(3).getReg() == 0;
if (MI->getOperand(1).isReg() && MI->getOperand(2).isImm() &&
MI->getOperand(3).isReg() && MI->getOperand(4).isCPI() &&
MI->getOperand(1).getReg() == 0 &&
MI->getOperand(2).getImm() == 1 &&
MI->getOperand(3).getReg() == 0)
return true;
return false;
}
// All other instructions marked M_REMATERIALIZABLE are always trivially
// rematerializable.
@ -168,32 +170,11 @@ bool X86InstrInfo::isReallySideEffectFree(MachineInstr *MI) const {
MI->getOperand(3).getReg() == 0)
return true;
}
// FALLTHROUGH
case X86::MOV8rm:
case X86::MOV16rm:
case X86::MOV16_rm:
case X86::MOV32_rm:
case X86::MOV64rm:
case X86::LD_Fp64m:
case X86::MOVSSrm:
case X86::MOVSDrm:
case X86::MOVAPSrm:
case X86::MOVAPDrm:
case X86::MMX_MOVD64rm:
case X86::MMX_MOVQ64rm:
// Loads from constant pools have no side effects
return MI->getOperand(1).isRegister() &&
MI->getOperand(2).isImmediate() &&
MI->getOperand(3).isRegister() &&
MI->getOperand(4).isConstantPoolIndex() &&
MI->getOperand(1).getReg() == 0 &&
MI->getOperand(2).getImm() == 1 &&
MI->getOperand(3).getReg() == 0;
break;
}
// All other instances of these instructions are presumed to have side
// effects.
return false;
// Anything that is rematerializable obviously has no side effects.
return isReallyTriviallyReMaterializable(MI);
}
/// hasLiveCondCodeDef - True if MI has a condition code def, e.g. EFLAGS, that