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Fix PR727, correctly handling large stack aligments on ppc 

llvm-svn: 27593
This commit is contained in:
Nate Begeman 2006-04-11 19:29:21 +00:00
parent aaa04230bd
commit 1bb132099f
1 changed files with 28 additions and 32 deletions
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60
llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp
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@ -202,12 +202,10 @@ static bool hasFP(const MachineFunction &MF) {
const MachineFrameInfo *MFI = MF.getFrameInfo(); const MachineFrameInfo *MFI = MF.getFrameInfo();
unsigned TargetAlign = MF.getTarget().getFrameInfo()->getStackAlignment(); unsigned TargetAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
// If frame pointers are forced, if there are variable sized stack objects, // If frame pointers are forced, or if there are variable sized stack objects,
// or if there is an object on the stack that requires more alignment than is // use a frame pointer.
// normally provided, use a frame pointer.
// //
return NoFramePointerElim || MFI->hasVarSizedObjects() || return NoFramePointerElim || MFI->hasVarSizedObjects();
MFI->getMaxAlignment() > TargetAlign;
} }
void PPCRegisterInfo:: void PPCRegisterInfo::
@ -396,15 +394,26 @@ void PPCRegisterInfo::emitPrologue(MachineFunction &MF) const {
int NegNumbytes = -NumBytes; int NegNumbytes = -NumBytes;
// Adjust stack pointer: r1 -= numbytes. // Adjust stack pointer: r1 -= numbytes.
if (NumBytes <= 32768) { // If there is a preferred stack alignment, align R1 now
BuildMI(MBB, MBBI, PPC::STWU, 3) if (MaxAlign > TargetAlign) {
.addReg(PPC::R1).addSImm(-NumBytes).addReg(PPC::R1); assert(isPowerOf2_32(MaxAlign) && MaxAlign < 32767 && "Invalid alignment!");
} else { assert(NumBytes <= 32768 && "Unhandled stack size and alignment combo!");
BuildMI(MBB, MBBI, PPC::LIS, 1, PPC::R0).addSImm(NegNumbytes >> 16); BuildMI(MBB, MBBI, PPC::RLWINM, 4, PPC::R0)
BuildMI(MBB, MBBI, PPC::ORI, 2, PPC::R0) .addReg(PPC::R1).addImm(0).addImm(32-Log2_32(MaxAlign)).addImm(31);
.addReg(PPC::R0).addImm(NegNumbytes & 0xFFFF); BuildMI(MBB, MBBI, PPC::SUBFIC,2,PPC::R0).addReg(PPC::R0).addSImm(MaxAlign);
BuildMI(MBB, MBBI, PPC::ADDI, 2, PPC::R0).addReg(PPC::R0)
.addSImm(NegNumbytes);
BuildMI(MBB, MBBI, PPC::STWUX, 3) BuildMI(MBB, MBBI, PPC::STWUX, 3)
.addReg(PPC::R1).addReg(PPC::R1).addReg(PPC::R0); .addReg(PPC::R1).addReg(PPC::R1).addReg(PPC::R0);
} else if (NumBytes <= 32768) {
BuildMI(MBB, MBBI, PPC::STWU, 3).addReg(PPC::R1).addSImm(NegNumbytes)
.addReg(PPC::R1);
} else {
BuildMI(MBB, MBBI, PPC::LIS, 1, PPC::R0).addSImm(NegNumbytes >> 16);
BuildMI(MBB, MBBI, PPC::ORI, 2, PPC::R0).addReg(PPC::R0)
.addImm(NegNumbytes & 0xFFFF);
BuildMI(MBB, MBBI, PPC::STWUX, 3).addReg(PPC::R1).addReg(PPC::R1)
.addReg(PPC::R0);
} }
if (DebugInfo && DebugInfo->hasInfo()) { if (DebugInfo && DebugInfo->hasInfo()) {
@ -419,19 +428,6 @@ void PPCRegisterInfo::emitPrologue(MachineFunction &MF) const {
BuildMI(MBB, MBBI, PPC::DWARF_LABEL, 1).addSImm(LabelID); BuildMI(MBB, MBBI, PPC::DWARF_LABEL, 1).addSImm(LabelID);
} }
// If there is a preferred stack alignment, align R1 now
// FIXME: If this ever matters, this could be made more efficient by folding
// this into the code above, so that we don't issue two store+update
// instructions.
if (MaxAlign > TargetAlign) {
assert(isPowerOf2_32(MaxAlign) && MaxAlign < 32767 && "Invalid alignment!");
BuildMI(MBB, MBBI, PPC::RLWINM, 4, PPC::R0)
.addReg(PPC::R1).addImm(0).addImm(32-Log2_32(MaxAlign)).addImm(31);
BuildMI(MBB, MBBI, PPC::SUBFIC, 2,PPC::R0).addReg(PPC::R0).addImm(MaxAlign);
BuildMI(MBB, MBBI, PPC::STWUX, 3)
.addReg(PPC::R1).addReg(PPC::R1).addReg(PPC::R0);
}
// If there is a frame pointer, copy R1 (SP) into R31 (FP) // If there is a frame pointer, copy R1 (SP) into R31 (FP)
if (HasFP) { if (HasFP) {
BuildMI(MBB, MBBI, PPC::STW, 3) BuildMI(MBB, MBBI, PPC::STW, 3)
@ -446,8 +442,12 @@ void PPCRegisterInfo::emitEpilogue(MachineFunction &MF,
assert(MBBI->getOpcode() == PPC::BLR && assert(MBBI->getOpcode() == PPC::BLR &&
"Can only insert epilog into returning blocks"); "Can only insert epilog into returning blocks");
// Get alignment info so we know how to restore r1
const MachineFrameInfo *MFI = MF.getFrameInfo();
unsigned TargetAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
// Get the number of bytes allocated from the FrameInfo. // Get the number of bytes allocated from the FrameInfo.
unsigned NumBytes = MF.getFrameInfo()->getStackSize(); unsigned NumBytes = MFI->getStackSize();
unsigned GPRSize = 4; unsigned GPRSize = 4;
if (NumBytes != 0) { if (NumBytes != 0) {
@ -460,15 +460,11 @@ void PPCRegisterInfo::emitEpilogue(MachineFunction &MF,
// The loaded (or persistent) stack pointer value is offseted by the 'stwu' // The loaded (or persistent) stack pointer value is offseted by the 'stwu'
// on entry to the function. Add this offset back now. // on entry to the function. Add this offset back now.
if (NumBytes < 32768) { if (NumBytes < 32768 && TargetAlign >= MFI->getMaxAlignment()) {
BuildMI(MBB, MBBI, PPC::ADDI, 2, PPC::R1) BuildMI(MBB, MBBI, PPC::ADDI, 2, PPC::R1)
.addReg(PPC::R1).addSImm(NumBytes); .addReg(PPC::R1).addSImm(NumBytes);
} else { } else {
BuildMI(MBB, MBBI, PPC::LIS, 1, PPC::R0).addSImm(NumBytes >> 16); BuildMI(MBB, MBBI, PPC::LWZ, 2, PPC::R1).addSImm(0).addReg(PPC::R1);
BuildMI(MBB, MBBI, PPC::ORI, 2, PPC::R0)
.addReg(PPC::R0).addImm(NumBytes & 0xFFFF);
BuildMI(MBB, MBBI, PPC::ADD4, 2, PPC::R1)
.addReg(PPC::R0).addReg(PPC::R1);
} }
} }
} }