[PATCH] D93497: Salvage debug info for function arguments in coro-split funclets.

Sun Jan 10 21:46:22 PST 2021

junparser added a comment.

In D93497#2488109 <https://reviews.llvm.org/D93497#2488109>, @aprantl wrote:

>> Do you have any plan to salvage debug info under O2 <https://reviews.llvm.org/owners/package/2/> when most of the dbg.declare are changed to dbg.value?
>
> I was hoping that in an optimization pipeline the coroutine splitting would be invoked //before// mem2reg. This patch is really depending on the semantics of dbg.declare, which guarantees that the address of the variable doesn't change throughout the entire function. With a dbg.value we don't have any such guarantees, since it's just a snapshot at one particular location.

Before mem2reg may solve this issue, however, it may cause performance regression (I'm not sure about this) since we design the pipeline  which heavily depend on cgscc. We may need fully test.

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https://reviews.llvm.org/D93497