}
}
+// 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();
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);
}
--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())) {