[PATCH] D45910: [BasicAA] Don't assume a PHI node has inputs

[Daniel Berlin via llvm-commits]

Trying to handle the invalid code we allow in unreachable blocks had so far
been a generally losing proposition. AFAIK we've always eventually given up
before getting any pass actually bug free.  Can we just stop asking aa
about this?



On Fri, Apr 20, 2018, 10:33 PM Craig Topper via Phabricator <
reviews at reviews.llvm.org> wrote:

> craig.topper added a comment.
>
> Sorry I meant it became unreachable during jump threading. And jump
> threading itself created the degenerate phi. The call into alias analysis
> also came from jump threading from SimplifyPartiallyRedundantLoad.
>
> But we do have our own internal changes in jump threading so its still
> possible that this is a problem there.
>
> I found other code that handles phis with no incoming values in the phi
> handling in computeKnownBitsFromOperator. That code is exercised by 3 lit
> tests, 2 of them due to jump threading.
>
>
> https://reviews.llvm.org/D45910
>
>
>
>
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