[PATCH] D69385: [RISCV] Fix CFA when doing split sp adjustment with fp

[Shiva Chen via Phabricator via llvm-commits]

shiva0217 accepted this revision.
shiva0217 added a comment.
This revision is now accepted and ready to land.

Hi @luismarques, thanks for the patch, LGTM.



================
Comment at: llvm/lib/Target/RISCV/RISCVFrameLowering.cpp:267
 
     adjustReg(MBB, LastFrameDestroy, DL, SPReg, SPReg, SecondSPAdjustAmount,
               MachineInstr::FrameDestroy);
----------------
luismarques wrote:
> shiva0217 wrote:
> > It seems that we might be able to reduce the epilogue instructions if the FP exists. Something like:
> > 
> >   
> >   if (hasFP(MF) && !isInt<12>(SecondSPAdjustAmount)) {
> >     adjustReg(MBB, LastFrameDestroy, DL, SPReg, FPReg,-FirstSPAdjustAmount + RVFI->getVarArgsSaveSize(), MachineInstr::FrameDestroy);
> >   } else {
> >     adjustReg(MBB, LastFrameDestroy, DL, SPReg, SPReg, SecondSPAdjustAmount, MachineInstr::FrameDestroy);
> >       // Emit ".cfi_def_cfa_offset FirstSPAdjustAmount"
> >       unsigned CFIIndex = MF.addFrameInst(
> >           MCCFIInstruction::createDefCfaOffset(nullptr, -FirstSPAdjustAmount));
> >       BuildMI(MBB, LastFrameDestroy, DL,
> >               TII->get(TargetOpcode::CFI_INSTRUCTION))
> >           .addCFIIndex(CFIIndex);
> >   }
> I would prefer to do codegen improvements in a separate patch. Thanks for the suggestion!
Ok, that makes sense.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D69385/new/

https://reviews.llvm.org/D69385