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Move merge code into new helper function.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42699 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Anton Korobeynikov 2007-10-06 16:17:49 +00:00
parent 81a788176e
commit 4f1c33f7c8
1 changed files with 34 additions and 43 deletions
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77
lib/Target/X86/X86RegisterInfo.cpp
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@ -1477,6 +1477,29 @@ void emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
}
}
// mergeSPUpdatesUp - Merge two stack-manipulating instructions upper iterator.
static
void mergeSPUpdatesUp(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
unsigned StackPtr, uint64_t *NumBytes = NULL) {
if (MBBI != MBB.begin()) {
MachineBasicBlock::iterator PI = prior(MBBI);
unsigned Opc = PI->getOpcode();
if ((Opc == X86::ADD64ri32 || Opc == X86::ADD64ri8 ||
Opc == X86::ADD32ri || Opc == X86::ADD32ri8) &&
PI->getOperand(0).getReg() == StackPtr) {
if (NumBytes)
*NumBytes += PI->getOperand(2).getImm();
MBB.erase(PI);
} else if ((Opc == X86::SUB64ri32 || Opc == X86::SUB64ri8 ||
Opc == X86::SUB32ri || Opc == X86::SUB32ri8) &&
PI->getOperand(0).getReg() == StackPtr) {
if (NumBytes)
*NumBytes -= PI->getOperand(2).getImm();
MBB.erase(PI);
}
}
}
void X86RegisterInfo::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
MachineFrameInfo *MFI = MF.getFrameInfo();
@ -1562,26 +1585,10 @@ void X86RegisterInfo::emitPrologue(MachineFunction &MF) const {
MBB.insert(MBBI, MI);
}
} else {
// If there is an ADD32ri or SUB32ri of ESP immediately after this
// If there is an ADD32ri or SUB32ri of ESP immediately before this
// instruction, merge the two instructions.
if (MBBI != MBB.end()) {
MachineBasicBlock::iterator NI = next(MBBI);
unsigned Opc = MBBI->getOpcode();
if ((Opc == X86::ADD64ri32 || Opc == X86::ADD64ri8 ||
Opc == X86::ADD32ri || Opc == X86::ADD32ri8) &&
MBBI->getOperand(0).getReg() == StackPtr) {
NumBytes -= MBBI->getOperand(2).getImm();
MBB.erase(MBBI);
MBBI = NI;
} else if ((Opc == X86::SUB64ri32 || Opc == X86::SUB64ri8 ||
Opc == X86::SUB32ri || Opc == X86::SUB32ri8) &&
MBBI->getOperand(0).getReg() == StackPtr) {
NumBytes += MBBI->getOperand(2).getImm();
MBB.erase(MBBI);
MBBI = NI;
}
}
mergeSPUpdatesUp(MBB, MBBI, StackPtr, &NumBytes);
if (NumBytes)
emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit, TII);
}
@ -1702,31 +1709,15 @@ void X86RegisterInfo::emitEpilogue(MachineFunction &MF,
--MBBI;
}
if (NumBytes || MFI->hasVarSizedObjects()) {
// If there is an ADD32ri or SUB32ri of ESP immediately before this
// instruction, merge the two instructions.
if (MBBI != MBB.begin()) {
MachineBasicBlock::iterator PI = prior(MBBI);
unsigned Opc = PI->getOpcode();
if ((Opc == X86::ADD64ri32 || Opc == X86::ADD64ri8 ||
Opc == X86::ADD32ri || Opc == X86::ADD32ri8) &&
PI->getOperand(0).getReg() == StackPtr) {
NumBytes += PI->getOperand(2).getImm();
MBB.erase(PI);
} else if ((Opc == X86::SUB64ri32 || Opc == X86::SUB64ri8 ||
Opc == X86::SUB32ri || Opc == X86::SUB32ri8) &&
PI->getOperand(0).getReg() == StackPtr) {
NumBytes -= PI->getOperand(2).getImm();
MBB.erase(PI);
}
}
}
// If there is an ADD32ri or SUB32ri of ESP immediately before this
// instruction, merge the two instructions.
if (NumBytes || MFI->hasVarSizedObjects())
mergeSPUpdatesUp(MBB, MBBI, StackPtr, &NumBytes);
// If dynamic alloca is used, then reset esp to point to the last
// callee-saved slot before popping them off!
// Also, if it's main() on Cygwin/Mingw32 we aligned stack in the prologue, - revert
// stack changes back. Note: we're assuming, that frame pointer was forced
// for main()
// If dynamic alloca is used, then reset esp to point to the last callee-saved
// slot before popping them off! Also, if it's main() on Cygwin/Mingw32 we
// aligned stack in the prologue, - revert stack changes back. Note: we're
// assuming, that frame pointer was forced for main()
if (MFI->hasVarSizedObjects() ||
(Fn->hasExternalLinkage() && Fn->getName() == "main" &&
Subtarget->isTargetCygMing())) {