[PATCH] D104440: [X86] Fix bug when X86 stackify pass handle one ArgFPRW.

Sun Jun 20 03:21:10 PDT 2021

LuoYuanke added a comment.

I think because I use the

In D104440#2829221 <https://reviews.llvm.org/D104440#2829221>, @craig.topper wrote:

> In D104440#2829220 <https://reviews.llvm.org/D104440#2829220>, @LuoYuanke wrote:
>
>> With -O0, the small case can also generate "IMPLICIT_DEF" and "CHS_Fp80". I think we are near to the root cause. Stay tuned.
>
> ProcessImplicitDefs doesn’t run with O0 and FP stackifier has special code for IMPLICIT_DEF.

This is because I set opt-bisect-limit=67436 in my command line. When CurBisectNum expired, "DAG to DAG" pass lower its opt level to O0. However "processimpdefs" and "X86 FP Stackifier" is not stopped due to the CurBisectNum expiration. So undefined fp0 is generated.

  if (OptLevel != CodeGenOpt::None && skipFunction(Fn))
    NewOptLevel = CodeGenOpt::None;
  OptLevelChanger OLC(*this, NewOptLevel);

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D104440/new/

https://reviews.llvm.org/D104440