[PATCH] D24854: [SROA] Drop lifetime.start/end intrinsics when they block promotion.

[Chandler Carruth via llvm-commits]

chandlerc added a comment.

Awesome, I'm glad this was so easy. Tiny nit picks below.



> SROA.cpp:2883-2884
> +    // promoted, but PromoteMemToReg doesn't handle that case.)
> +    // FIXME: Check whether the alloca is promotable before dropping the
> +    // lifetime intrinsics?
> +    bool IsWholeAlloca = NewBeginOffset == NewAllocaBeginOffset &&

We also don't want to do this if the function is being instrumented by ASan as this will undermine scope checking using lifetime markers.

> SROA.cpp:2885-2887
> +    bool IsWholeAlloca = NewBeginOffset == NewAllocaBeginOffset &&
> +                         NewEndOffset == NewAllocaEndOffset;
> +    if (!IsWholeAlloca)

Since we just always can promote through lifetime intrinsics now, I would skip the variable entirely.

Repository:
  rL LLVM

https://reviews.llvm.org/D24854