[PATCH] D137642: [X86][CodeGen] Fix crash in hotpatch

Fri Nov 18 13:03:19 PST 2022

saudi added a comment.

In D137642#3934867 <https://reviews.llvm.org/D137642#3934867>, @rnk wrote:

> I was going to approve it as is, since it looks like a correct simplification.
>
> Relatedly, @dblaikie was considering establishing the invariant that all empty functions have at least one trap instruction, although for this code the entry BB could conceivably be empty, and you should handle that.

I will update this patch to better handle the case of an empty entry BB.

Also, I encountered another issue with -fms-hotpatch, which looks more involved: currently, lowering `PATCHABLE_OP` may not lower the wrapped instruction properly. 
I created an issue for it: https://github.com/llvm/llvm-project/issues/59039 
I could keep that for another patch, but as it is pretty related it may be worth combining into a patch that completely fixes the feature.
WDYT?

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D137642/new/

https://reviews.llvm.org/D137642