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[AArch64] NFC: Rename LastPopI in emitEpilogue #156884

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Sep 5, 2025
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[AArch64] NFC: Rename LastPopI in emitEpilogue #156884

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45 changes: 23 additions & 22 deletions llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2548,15 +2548,15 @@ void AArch64FrameLowering::emitEpilogue(MachineFunction &MF,
AFI->setLocalStackSize(NumBytes - PrologueSaveSize);
if (homogeneousPrologEpilog(MF, &MBB)) {
assert(!NeedsWinCFI);
auto LastPopI = MBB.getFirstTerminator();
if (LastPopI != MBB.begin()) {
auto HomogeneousEpilog = std::prev(LastPopI);
auto FirstHomogenousEpilogI = MBB.getFirstTerminator();
if (FirstHomogenousEpilogI != MBB.begin()) {
auto HomogeneousEpilog = std::prev(FirstHomogenousEpilogI);
if (HomogeneousEpilog->getOpcode() == AArch64::HOM_Epilog)
LastPopI = HomogeneousEpilog;
FirstHomogenousEpilogI = HomogeneousEpilog;
}

// Adjust local stack
emitFrameOffset(MBB, LastPopI, DL, AArch64::SP, AArch64::SP,
emitFrameOffset(MBB, FirstHomogenousEpilogI, DL, AArch64::SP, AArch64::SP,
StackOffset::getFixed(AFI->getLocalStackSize()), TII,
MachineInstr::FrameDestroy, false, NeedsWinCFI, &HasWinCFI);

Expand Down Expand Up @@ -2602,17 +2602,17 @@ void AArch64FrameLowering::emitEpilogue(MachineFunction &MF,
// Move past the restores of the callee-saved registers.
// If we plan on combining the sp bump of the local stack size and the callee
// save stack size, we might need to adjust the CSR save and restore offsets.
MachineBasicBlock::iterator LastPopI = MBB.getFirstTerminator();
MachineBasicBlock::iterator FirstGPRRestoreI = MBB.getFirstTerminator();
MachineBasicBlock::iterator Begin = MBB.begin();
while (LastPopI != Begin) {
--LastPopI;
if (!LastPopI->getFlag(MachineInstr::FrameDestroy) ||
(!FPAfterSVECalleeSaves && IsSVECalleeSave(LastPopI))) {
++LastPopI;
while (FirstGPRRestoreI != Begin) {
--FirstGPRRestoreI;
if (!FirstGPRRestoreI->getFlag(MachineInstr::FrameDestroy) ||
(!FPAfterSVECalleeSaves && IsSVECalleeSave(FirstGPRRestoreI))) {
++FirstGPRRestoreI;
break;
} else if (CombineSPBump)
fixupCalleeSaveRestoreStackOffset(*LastPopI, AFI->getLocalStackSize(),
NeedsWinCFI, &HasWinCFI);
fixupCalleeSaveRestoreStackOffset(
*FirstGPRRestoreI, AFI->getLocalStackSize(), NeedsWinCFI, &HasWinCFI);
}

if (NeedsWinCFI) {
Expand All @@ -2622,9 +2622,9 @@ void AArch64FrameLowering::emitEpilogue(MachineFunction &MF,
// arguments. Insert the SEH_EpilogStart and remove it later if it
// we didn't emit any SEH opcodes to avoid generating WinCFI for
// functions that don't need it.
BuildMI(MBB, LastPopI, DL, TII->get(AArch64::SEH_EpilogStart))
BuildMI(MBB, FirstGPRRestoreI, DL, TII->get(AArch64::SEH_EpilogStart))
.setMIFlag(MachineInstr::FrameDestroy);
EpilogStartI = LastPopI;
EpilogStartI = FirstGPRRestoreI;
--EpilogStartI;
}

Expand Down Expand Up @@ -2665,7 +2665,7 @@ void AArch64FrameLowering::emitEpilogue(MachineFunction &MF,

// When we are about to restore the CSRs, the CFA register is SP again.
if (EmitCFI && hasFP(MF))
CFIInstBuilder(MBB, LastPopI, MachineInstr::FrameDestroy)
CFIInstBuilder(MBB, FirstGPRRestoreI, MachineInstr::FrameDestroy)
.buildDefCFA(AArch64::SP, NumBytes);

emitFrameOffset(MBB, MBB.getFirstTerminator(), DL, AArch64::SP, AArch64::SP,
Expand All @@ -2681,7 +2681,8 @@ void AArch64FrameLowering::emitEpilogue(MachineFunction &MF,
// Process the SVE callee-saves to determine what space needs to be
// deallocated.
StackOffset DeallocateBefore = {}, DeallocateAfter = SVEStackSize;
MachineBasicBlock::iterator RestoreBegin = LastPopI, RestoreEnd = LastPopI;
MachineBasicBlock::iterator RestoreBegin = FirstGPRRestoreI,
RestoreEnd = FirstGPRRestoreI;
if (int64_t CalleeSavedSize = AFI->getSVECalleeSavedStackSize()) {
if (FPAfterSVECalleeSaves)
RestoreEnd = MBB.getFirstTerminator();
Expand All @@ -2706,7 +2707,7 @@ void AArch64FrameLowering::emitEpilogue(MachineFunction &MF,
// deallocates non-callee-save SVE allocations. Otherwise, deallocate
// them explicitly.
if (!AFI->isStackRealigned() && !MFI.hasVarSizedObjects()) {
emitFrameOffset(MBB, LastPopI, DL, AArch64::SP, AArch64::SP,
emitFrameOffset(MBB, FirstGPRRestoreI, DL, AArch64::SP, AArch64::SP,
DeallocateBefore, TII, MachineInstr::FrameDestroy, false,
NeedsWinCFI, &HasWinCFI);
}
Expand Down Expand Up @@ -2796,7 +2797,7 @@ void AArch64FrameLowering::emitEpilogue(MachineFunction &MF,
StackRestoreBytes += AfterCSRPopSize;

emitFrameOffset(
MBB, LastPopI, DL, AArch64::SP, AArch64::SP,
MBB, FirstGPRRestoreI, DL, AArch64::SP, AArch64::SP,
StackOffset::getFixed(StackRestoreBytes), TII,
MachineInstr::FrameDestroy, false, NeedsWinCFI, &HasWinCFI, EmitCFI,
StackOffset::getFixed((RedZone ? 0 : NumBytes) + PrologueSaveSize));
Expand All @@ -2816,17 +2817,17 @@ void AArch64FrameLowering::emitEpilogue(MachineFunction &MF,
// be able to save any instructions.
if (!IsFunclet && (MFI.hasVarSizedObjects() || AFI->isStackRealigned())) {
emitFrameOffset(
MBB, LastPopI, DL, AArch64::SP, AArch64::FP,
MBB, FirstGPRRestoreI, DL, AArch64::SP, AArch64::FP,
StackOffset::getFixed(-AFI->getCalleeSaveBaseToFrameRecordOffset()),
TII, MachineInstr::FrameDestroy, false, NeedsWinCFI, &HasWinCFI);
} else if (NumBytes)
emitFrameOffset(MBB, LastPopI, DL, AArch64::SP, AArch64::SP,
emitFrameOffset(MBB, FirstGPRRestoreI, DL, AArch64::SP, AArch64::SP,
StackOffset::getFixed(NumBytes), TII,
MachineInstr::FrameDestroy, false, NeedsWinCFI, &HasWinCFI);

// When we are about to restore the CSRs, the CFA register is SP again.
if (EmitCFI && hasFP(MF))
CFIInstBuilder(MBB, LastPopI, MachineInstr::FrameDestroy)
CFIInstBuilder(MBB, FirstGPRRestoreI, MachineInstr::FrameDestroy)
.buildDefCFA(AArch64::SP, PrologueSaveSize);

// This must be placed after the callee-save restore code because that code
Expand Down