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[PPC][AIX] Save/restore r31 when using base pointer #100182

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Merged
syzaara merged 5 commits into from
Aug 7, 2024
Merged

[PPC][AIX] Save/restore r31 when using base pointer #100182

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e5fd2aa
[PPC][AIX] Set needsFP to true when base pointer is used in prologue/…
Jul 23, 2024
069da92
Address review comments
Jul 29, 2024
f379cf4
Address review comments, fix formatting
Jul 29, 2024
d0a2452
Address review comments
Aug 1, 2024
4545ed6
Fix testcase comment
Aug 1, 2024
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25 changes: 13 additions & 12 deletions llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -696,7 +696,7 @@ void PPCFrameLowering::emitPrologue(MachineFunction &MF,
int64_t LROffset = getReturnSaveOffset();

int64_t FPOffset = 0;
if (HasFP) {
if (HasFP || (HasBP && Subtarget.isAIXABI())) {
MachineFrameInfo &MFI = MF.getFrameInfo();
int FPIndex = FI->getFramePointerSaveIndex();
assert(FPIndex && "No Frame Pointer Save Slot!");
Expand Down Expand Up @@ -821,7 +821,7 @@ void PPCFrameLowering::emitPrologue(MachineFunction &MF,
BuildMoveFromCR();

if (HasRedZone) {
if (HasFP)
if (HasFP || (HasBP && Subtarget.isAIXABI()))
BuildMI(MBB, MBBI, dl, StoreInst)
.addReg(FPReg)
.addImm(FPOffset)
Expand Down Expand Up @@ -1007,7 +1007,7 @@ void PPCFrameLowering::emitPrologue(MachineFunction &MF,
// R0 cannot be used as a base register, but it can be used as an
// index in a store-indexed.
int LastOffset = 0;
if (HasFP) {
if (HasFP || (HasBP && Subtarget.isAIXABI())) {
// R0 += (FPOffset-LastOffset).
// Need addic, since addi treats R0 as 0.
BuildMI(MBB, MBBI, dl, TII.get(PPC::ADDIC), ScratchReg)
Expand Down Expand Up @@ -1052,7 +1052,7 @@ void PPCFrameLowering::emitPrologue(MachineFunction &MF,

// Now that the stack frame has been allocated, save all the necessary
// registers using ScratchReg as the base address.
if (HasFP)
if (HasFP || (HasBP && Subtarget.isAIXABI()))
BuildMI(MBB, MBBI, dl, StoreInst)
.addReg(FPReg)
.addImm(FPOffset)
Expand All @@ -1077,7 +1077,7 @@ void PPCFrameLowering::emitPrologue(MachineFunction &MF,
// field of STWU). To be here we have to be compiling for PPC32.
// Since the SPReg has been decreased by FrameSize, add it back to each
// offset.
if (HasFP)
if (HasFP || (HasBP && Subtarget.isAIXABI()))
BuildMI(MBB, MBBI, dl, StoreInst)
.addReg(FPReg)
.addImm(FrameSize + FPOffset)
Expand Down Expand Up @@ -1123,7 +1123,7 @@ void PPCFrameLowering::emitPrologue(MachineFunction &MF,
BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION))
.addCFIIndex(CFIIndex);

if (HasFP) {
if (HasFP || (HasBP && Subtarget.isAIXABI())) {
// Describe where FP was saved, at a fixed offset from CFA.
unsigned Reg = MRI->getDwarfRegNum(FPReg, true);
CFIIndex = MF.addFrameInst(
Expand Down Expand Up @@ -1606,7 +1606,7 @@ void PPCFrameLowering::emitEpilogue(MachineFunction &MF,

SingleScratchReg = ScratchReg == TempReg;

if (HasFP) {
if (HasFP || (HasBP && Subtarget.isAIXABI())) {
int FPIndex = FI->getFramePointerSaveIndex();
assert(FPIndex && "No Frame Pointer Save Slot!");
FPOffset = MFI.getObjectOffset(FPIndex);
Expand Down Expand Up @@ -1802,7 +1802,7 @@ void PPCFrameLowering::emitEpilogue(MachineFunction &MF,
.addReg(RBReg);
}

if (HasFP) {
if (HasFP || (HasBP && Subtarget.isAIXABI())) {
// If there is red zone, restore FP directly, since SP has already been
// restored. Otherwise, restore the value of FP into ScratchReg.
if (HasRedZone || RBReg == SPReg)
Expand Down Expand Up @@ -1994,7 +1994,8 @@ void PPCFrameLowering::determineCalleeSaves(MachineFunction &MF,
MachineFrameInfo &MFI = MF.getFrameInfo();

// If the frame pointer save index hasn't been defined yet.
if (!FPSI && needsFP(MF)) {
if (!FPSI &&
(needsFP(MF) || (RegInfo->hasBasePointer(MF) && Subtarget.isAIXABI()))) {
// Find out what the fix offset of the frame pointer save area.
int FPOffset = getFramePointerSaveOffset();
// Allocate the frame index for frame pointer save area.
Expand Down Expand Up @@ -2023,7 +2024,7 @@ void PPCFrameLowering::determineCalleeSaves(MachineFunction &MF,
// some inline asm which explicitly clobbers it, when we otherwise have a
// frame pointer and are using r31's spill slot for the prologue/epilogue
// code. Same goes for the base pointer and the PIC base register.
if (needsFP(MF))
if (needsFP(MF) || (RegInfo->hasBasePointer(MF) && Subtarget.isAIXABI()))
SavedRegs.reset(isPPC64 ? PPC::X31 : PPC::R31);
if (RegInfo->hasBasePointer(MF))
SavedRegs.reset(RegInfo->getBaseRegister(MF));
Expand Down Expand Up @@ -2166,9 +2167,10 @@ void PPCFrameLowering::processFunctionBeforeFrameFinalized(MachineFunction &MF,
LowerBound -= (31 - TRI->getEncodingValue(MinFPR) + 1) * 8;
}

const PPCRegisterInfo *RegInfo = Subtarget.getRegisterInfo();
// Check whether the frame pointer register is allocated. If so, make sure it
// is spilled to the correct offset.
if (needsFP(MF)) {
if (needsFP(MF) || (RegInfo->hasBasePointer(MF) && Subtarget.isAIXABI())) {
int FI = PFI->getFramePointerSaveIndex();
assert(FI && "No Frame Pointer Save Slot!");
MFI.setObjectOffset(FI, LowerBound + MFI.getObjectOffset(FI));
Expand All @@ -2185,7 +2187,6 @@ void PPCFrameLowering::processFunctionBeforeFrameFinalized(MachineFunction &MF,
HasGPSaveArea = true;
}

const PPCRegisterInfo *RegInfo = Subtarget.getRegisterInfo();
if (RegInfo->hasBasePointer(MF)) {
int FI = PFI->getBasePointerSaveIndex();
assert(FI && "No Base Pointer Save Slot!");
Expand Down
7 changes: 6 additions & 1 deletion llvm/test/CodeGen/PowerPC/aix-base-pointer.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -6,8 +6,9 @@

; Use an overaligned buffer to force base-pointer usage. Test verifies:
; - base pointer register (r30) is saved/defined/restored.
; - frame pointer register (r31) is saved/defined/restored.
; - stack frame is allocated with correct alignment.
; - Address of %AlignedBuffer is calculated based off offset from the stack
; - Address of %AlignedBuffer is calculated based off offset from the frame
; pointer.

define float @caller(float %f) {
Expand All @@ -19,6 +20,7 @@ define float @caller(float %f) {
declare void @callee(ptr)

; 32BIT-LABEL: .caller:
; 32BIT: stw 31, -12(1)
; 32BIT: stw 30, -16(1)
; 32BIT: mr 30, 1
; 32BIT: clrlwi 0, 1, 27
Expand All @@ -27,9 +29,11 @@ declare void @callee(ptr)
; 32BIT: addi 3, 1, 64
; 32BIT: bl .callee
; 32BIT: mr 1, 30
; 32BIT: lwz 31, -12(1)
; 32BIT: lwz 30, -16(1)

; 64BIT-LABEL: .caller:
; 64BIT: std 31, -16(1)
; 64BIT: std 30, -24(1)
; 64BIT: mr 30, 1
; 64BIT: clrldi 0, 1, 59
Expand All @@ -38,4 +42,5 @@ declare void @callee(ptr)
; 64BIT: addi 3, 1, 128
; 64BIT: bl .callee
; 64BIT: mr 1, 30
; 64BIT: ld 31, -16(1)
; 64BIT: ld 30, -24(1)
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