if (AFI->getVarArgsRegSaveSize() > 0)
MF.getRegInfo().setPhysRegUsed(ARM::LR);
- // Spill R4 if Thumb1 epilogue has to restore SP from FP since
+ // Spill R4 if Thumb1 epilogue has to restore SP from FP. We don't know
+ // for sure what the stack size will be, but for this, an estimate is good
+ // enough. If there anything changes it, it'll be a spill, which implies
+ // we've used all the registers and so R4 is already used, so not marking
+ // it here will be OK.
// FIXME: It will be better just to find spare register here.
- if (MFI->hasVarSizedObjects())
+ unsigned StackSize = estimateStackSize(MF);
+ if (MFI->hasVarSizedObjects() || StackSize > 508)
MF.getRegInfo().setPhysRegUsed(ARM::R4);
}
BuildMI(MBB, MBBI, dl, TII.get(ARM::tADDrSPi), FramePtr)
.addFrameIndex(FramePtrSpillFI).addImm(0)
.setMIFlags(MachineInstr::FrameSetup);
- if (NumBytes > 7)
- // If offset is > 7 then sp cannot be adjusted in a single instruction,
+ if (NumBytes > 508)
+ // If offset is > 508 then sp cannot be adjusted in a single instruction,
// try restoring from fp instead.
AFI->setShouldRestoreSPFromFP(true);
}