[llvm-bugs] [Bug 50500] Miscompile with SLP vectorizer + instcombine

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=50500

Sanjay Patel <spatel+llvm at rotateright.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
 Fixed By Commit(s)|                            |7bb8bfa0622b
         Resolution|---                         |FIXED

--- Comment #2 from Sanjay Patel <spatel+llvm at rotateright.com> ---
As with bug 49832, it's more general than partial undef - we don't account for
vector transforms in our equivalence substituation logic:
https://reviews.llvm.org/rG7bb8bfa0622b

I audited callers and don't see any other places we could hit this, so I put an
assert in the simplify code. 

If we want this kind of transform for vectors, we might try to handle splats
only, but I don't see any evidence for it.

I think this bug was completely hidden before D101191, so it doesn't affect
release branches, but feel free to reopen if that's not right.

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