[PATCH] D93586: [InstCombine] use poison as placeholder for undemanded elems

Tue Dec 22 09:27:26 PST 2020

spatel added a comment.

In D93586#2467248 <https://reviews.llvm.org/D93586#2467248>, @aqjune wrote:

>> There are 792 files in llvm/test, most of which are in test/Transform (119) and test/CodeGen(655).
>> The transition will be swiftly done (if there's no other issue hopefully) by the next weekend.
>
> Thinking about these again, do we need to make a poison copy for test/CodeGen? I don't think so, since the backend won't be changed anyway.

It would be good to update those for consistency; the codegen tests are supposed to be representative of what comes out of the IR optimizer. IIUC, we could do the substitution on those files already, and it would not change anything. But let's sort out the IR changes first?

In D93586#2466284 <https://reviews.llvm.org/D93586#2466284>, @aqjune wrote:

> My concern is that some tests aren't using `utils/update_test_checks.py`, and this makes things complicated. :(
> Simply replacing `insertelement undef` at `CHECK:` isn't enough (ex: Transforms/SLPVectorizer/X86/alternate-cast.ll).

Yes, tests that don't have scripted CHECK lines require more work to understand. That SLP test file is scripted though. Is there another problem with that one?

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https://reviews.llvm.org/D93586