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Fix one more Thumb eliminateFrameIndex bug. 

llvm-svn: 34990
This commit is contained in:
Evan Cheng 2007-03-07 00:12:18 +00:00
parent 4fd528f213
commit 67038e7a8b
1 changed files with 23 additions and 9 deletions
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32
llvm/lib/Target/ARM/ARMRegisterInfo.cpp
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@ -398,7 +398,7 @@ static unsigned calcNumMI(int Opc, int ExtraOpc, unsigned Bytes,
Bytes -= ThisVal;
NumMIs++;
NumBits = 8;
Scale = 1;
Scale = 1; // Followed by a number of tADDi8.
Chunk = ((1 << NumBits) - 1) * Scale;
}
@ -685,7 +685,7 @@ void ARMRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
const TargetInstrDescriptor &Desc = TII.get(Opcode);
unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
bool isSub = false;
if (Opcode == ARM::ADDri) {
Offset += MI.getOperand(i+1).getImm();
if (Offset == 0) {
@ -724,8 +724,21 @@ void ARMRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
MI.getOperand(i+1).ChangeToImmediate(ThisSOImmVal);
} else if (Opcode == ARM::tADDrSPi) {
Offset += MI.getOperand(i+1).getImm();
assert((Offset & 3) == 0 &&
"Thumb add/sub sp, #imm immediate must be multiple of 4!");
// Can't use tADDrSPi if it's based off the frame pointer.
unsigned NumBits = 0;
unsigned Scale = 1;
if (FrameReg != ARM::SP) {
Opcode = ARM::tADDi3;
MI.setInstrDescriptor(TII.get(ARM::tADDi3));
NumBits = 3;
} else {
NumBits = 8;
Scale = 4;
assert((Offset & 3) == 0 &&
"Thumb add/sub sp, #imm immediate must be multiple of 4!");
}
if (Offset == 0) {
// Turn it into a move.
MI.setInstrDescriptor(TII.get(ARM::tMOVrr));
@ -735,16 +748,17 @@ void ARMRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
}
// Common case: small offset, fits into instruction.
if (((Offset >> 2) & ~255U) == 0) {
unsigned Mask = (1 << NumBits) - 1;
if (((Offset / Scale) & ~Mask) == 0) {
// Replace the FrameIndex with sp / fp
MI.getOperand(i).ChangeToRegister(FrameReg, false);
MI.getOperand(i+1).ChangeToImmediate(Offset >> 2);
MI.getOperand(i+1).ChangeToImmediate(Offset / Scale);
return;
}
unsigned DestReg = MI.getOperand(0).getReg();
unsigned Bytes = (Offset > 0) ? Offset : -Offset;
unsigned NumMIs = calcNumMI(Opcode, 0, Bytes, 8, 1);
unsigned NumMIs = calcNumMI(Opcode, 0, Bytes, NumBits, Scale);
// MI would expand into a large number of instructions. Don't try to
// simplify the immediate.
if (NumMIs > 2) {
@ -758,8 +772,8 @@ void ARMRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
// 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 * 4);
MI.getOperand(i+1).ChangeToImmediate(Mask);
Offset = (Offset - Mask * Scale);
MachineBasicBlock::iterator NII = next(II);
emitThumbRegPlusImmediate(MBB, NII, DestReg, DestReg, Offset, TII);
} else {