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When emitting instructions that define EFLAGS and the EFLAGS value isn't 

used, mark the defs as dead.

llvm-svn: 61215
This commit is contained in:
Dan Gohman 2008-12-18 22:03:42 +00:00
parent 975f78ae79
commit 69cd963b9a
1 changed files with 23 additions and 7 deletions
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30
llvm/lib/Target/X86/X86RegisterInfo.cpp
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@ -403,6 +403,9 @@ eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
}
}
// The EFLAGS implicit def is dead.
New->getOperand(3).setIsDead();
// Replace the pseudo instruction with a new instruction...
if (New) MBB.insert(I, New);
}
@ -416,6 +419,9 @@ eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
(Is64Bit ? X86::SUB64ri32 : X86::SUB32ri);
MachineInstr *New =
BuildMI(MF, TII.get(Opc), StackPtr).addReg(StackPtr).addImm(CalleeAmt);
// The EFLAGS implicit def is dead.
New->getOperand(3).setIsDead();
MBB.insert(I, New);
}
}
@ -517,7 +523,10 @@ void emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
while (Offset) {
uint64_t ThisVal = (Offset > Chunk) ? Chunk : Offset;
BuildMI(MBB, MBBI, TII.get(Opc), StackPtr).addReg(StackPtr).addImm(ThisVal);
MachineInstr *MI =
BuildMI(MBB, MBBI, TII.get(Opc), StackPtr).addReg(StackPtr).addImm(ThisVal);
// The EFLAGS implicit def is dead.
MI->getOperand(3).setIsDead();
Offset -= ThisVal;
}
}
@ -713,8 +722,11 @@ void X86RegisterInfo::emitPrologue(MachineFunction &MF) const {
// applies to tail call optimized functions where the callee argument stack
// size is bigger than the callers.
if (TailCallReturnAddrDelta < 0) {
BuildMI(MBB, MBBI, TII.get(Is64Bit? X86::SUB64ri32 : X86::SUB32ri),
StackPtr).addReg(StackPtr).addImm(-TailCallReturnAddrDelta);
MachineInstr *MI =
BuildMI(MBB, MBBI, TII.get(Is64Bit? X86::SUB64ri32 : X86::SUB32ri),
StackPtr).addReg(StackPtr).addImm(-TailCallReturnAddrDelta);
// The EFLAGS implicit def is dead.
MI->getOperand(3).setIsDead();
}
uint64_t NumBytes = 0;
@ -751,10 +763,14 @@ void X86RegisterInfo::emitPrologue(MachineFunction &MF) const {
I->addLiveIn(FramePtr);
// Realign stack
if (needsStackRealignment(MF))
BuildMI(MBB, MBBI,
TII.get(Is64Bit ? X86::AND64ri32 : X86::AND32ri),
StackPtr).addReg(StackPtr).addImm(-MaxAlign);
if (needsStackRealignment(MF)) {
MachineInstr *MI =
BuildMI(MBB, MBBI,
TII.get(Is64Bit ? X86::AND64ri32 : X86::AND32ri),
StackPtr).addReg(StackPtr).addImm(-MaxAlign);
// The EFLAGS implicit def is dead.
MI->getOperand(3).setIsDead();
}
} else
NumBytes = StackSize - X86FI->getCalleeSavedFrameSize();