[PATCH] D92803: [SystemZFrameLowering] Make sure R1 holding the backchain is not corrupted by probing

[Ulrich Weigand via Phabricator via llvm-commits]

uweigand added a comment.

I think it still makes sense to have the backchain store local in inlineStackProbe.

In fact, I think it would be best to have the backchain store in every iteration of the loop, i.e. to the store in allocateAndProbe (of course that means the store then implicitly acts as probe so we don't need the volatile compare any more if we have a backchain).

  // The back chain is stored topmost with packed-stack.
  int Offset = usePackedStack(MF) ? SystemZMC::CallFrameSize - 8 : 0;

Given that this is now duplicated, maybe it would make sense to have that logic in a separate function "getBackchainOffset(MF)" or the like.


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  https://reviews.llvm.org/D92803/new/

https://reviews.llvm.org/D92803