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[SystemZ][z/OS] Make emitIncrement() a member function of SystemZFrameLowering. (#188254)

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Function `emitIncrement()` uses 8 for stack alignment, but the stack
alignment for 64-bit XPLINK is 32 on z/OS.
This PR changes it to a member function of SystemZFrameLowering to get
the correct stack alignment by `getStackAlignment()`. It also adds a
test to verify it.
This commit is contained in:
sujianIBM 2026-03-25 09:24:59 -04:00 committed by GitHub
parent 314a94c26f
commit bbc1ce04b2
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
3 changed files with 46 additions and 28 deletions
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57
llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
View File

@ -162,6 +162,35 @@ bool SystemZFrameLowering::hasReservedCallFrame(
return true;
}
void SystemZFrameLowering::emitIncrement(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI,
const DebugLoc &DL, Register Reg,
int64_t NumBytes,
const TargetInstrInfo *TII) const {
while (NumBytes) {
unsigned Opcode;
int64_t ThisVal = NumBytes;
if (isInt<16>(NumBytes))
Opcode = SystemZ::AGHI;
else {
Opcode = SystemZ::AGFI;
// Make sure we maintain stack alignment.
int64_t MinVal = -uint64_t(1) << 31;
int64_t MaxVal = (int64_t(1) << 31) - getStackAlignment();
if (ThisVal < MinVal)
ThisVal = MinVal;
else if (ThisVal > MaxVal)
ThisVal = MaxVal;
}
MachineInstr *MI = BuildMI(MBB, MBBI, DL, TII->get(Opcode), Reg)
.addReg(Reg)
.addImm(ThisVal);
// The CC implicit def is dead.
MI->getOperand(3).setIsDead();
NumBytes -= ThisVal;
}
}
bool SystemZELFFrameLowering::assignCalleeSavedSpillSlots(
MachineFunction &MF, const TargetRegisterInfo *TRI,
std::vector<CalleeSavedInfo> &CSI) const {
@ -474,34 +503,6 @@ void SystemZELFFrameLowering::processFunctionBeforeFrameFinalized(
MO.setIsKill(false);
}
// Emit instructions before MBBI (in MBB) to add NumBytes to Reg.
static void emitIncrement(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI, const DebugLoc &DL,
Register Reg, int64_t NumBytes,
const TargetInstrInfo *TII) {
while (NumBytes) {
unsigned Opcode;
int64_t ThisVal = NumBytes;
if (isInt<16>(NumBytes))
Opcode = SystemZ::AGHI;
else {
Opcode = SystemZ::AGFI;
// Make sure we maintain 8-byte stack alignment.
int64_t MinVal = -uint64_t(1) << 31;
int64_t MaxVal = (int64_t(1) << 31) - 8;
if (ThisVal < MinVal)
ThisVal = MinVal;
else if (ThisVal > MaxVal)
ThisVal = MaxVal;
}
MachineInstr *MI = BuildMI(MBB, MBBI, DL, TII->get(Opcode), Reg)
.addReg(Reg).addImm(ThisVal);
// The CC implicit def is dead.
MI->getOperand(3).setIsDead();
NumBytes -= ThisVal;
}
}
// Add CFI for the new CFA offset.
static void buildCFAOffs(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,

5
llvm/lib/Target/SystemZ/SystemZFrameLowering.h
View File

@ -54,6 +54,11 @@ public:
// Return the size of a pointer (in bytes).
unsigned getPointerSize() const { return PointerSize; }
// Emit instructions before MBBI (in MBB) to add NumBytes to Reg.
void emitIncrement(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
const DebugLoc &DL, Register Reg, int64_t NumBytes,
const TargetInstrInfo *TII) const;
private:
unsigned PointerSize;
};

12
llvm/test/CodeGen/SystemZ/zos-prologue-epilog.ll
View File

@ -400,6 +400,18 @@ define void @large_stack2(i64 %n1, i64 %n2, i64 %n3) {
ret void
}
; Verify stack alignment is 32
; CHECK-LABEL: large_stack3
; CHECK: agfi 4,-2147483648
; CHECK-NEXT: aghi 4,-224
; CHECK: agfi 4,2147483616
; CHECK-NEXT: aghi 4,256
define void @large_stack3() {
%arr = alloca [268435457 x i64], align 8
call i64 (ptr) @fun1(ptr %arr)
ret void
}
; CHECK-LABEL: L#EPM_leaf_func0_0 DS 0H
; CHECK: * DSA Size 0x0
; CHECK: * Entry Flags