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Another thumb large stack offset codegen bug. 

llvm-svn: 33795
This commit is contained in:
Evan Cheng 2007-02-02 21:08:39 +00:00
parent 3e667f3e61
commit f089c99f1d
1 changed files with 13 additions and 5 deletions
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18
llvm/lib/Target/ARM/ARMRegisterInfo.cpp
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@ -625,7 +625,6 @@ void ARMRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II) const{
Offset += MI.getOperand(i+1).getImm();
assert((Offset & 3) == 0 &&
"Thumb add/sub sp, #imm immediate must be multiple of 4!");
Offset >>= 2;
if (Offset == 0) {
// Turn it into a move.
MI.setInstrDescriptor(TII.get(ARM::tMOVrr));
@ -635,28 +634,37 @@ void ARMRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II) const{
}
// Common case: small offset, fits into instruction.
if ((Offset & ~255U) == 0) {
if (((Offset >> 2) & ~255U) == 0) {
// Replace the FrameIndex with sp / fp
MI.getOperand(i).ChangeToRegister(FrameReg, false);
MI.getOperand(i+1).ChangeToImmediate(Offset);
MI.getOperand(i+1).ChangeToImmediate(Offset >> 2);
return;
}
unsigned DestReg = MI.getOperand(0).getReg();
unsigned Bytes = (Offset > 0) ? Offset : -Offset;
unsigned NumMIs = calcNumMI(Opcode, 0, Bytes, 8, 1);
// MI would expand into a large number of instructions. Don't try to
// simplify the immediate.
if (NumMIs > 2) {
emitThumbRegPlusImmediate(MBB, II, DestReg, ARM::SP, Offset, TII);
MBB.erase(II);
return;
}
if (Offset > 0) {
// Translate r0 = add sp, imm to
// r0 = add sp, 255*4
// r0 = add r0, (imm - 255*4)
MI.getOperand(i).ChangeToRegister(FrameReg, false);
MI.getOperand(i+1).ChangeToImmediate(255);
Offset = (Offset - 255) << 2;
Offset = (Offset - 255 * 4);
MachineBasicBlock::iterator NII = next(II);
emitThumbRegPlusImmediate(MBB, NII, DestReg, DestReg, Offset, TII);
} else {
// Translate r0 = add sp, -imm to
// r0 = -imm (this is then translated into a series of instructons)
// r0 = add r0, sp
Offset <<= 2;
emitThumbConstant(MBB, II, DestReg, Offset, TII);
MI.setInstrDescriptor(TII.get(ARM::tADDhirr));
MI.getOperand(i).ChangeToRegister(DestReg, false);