[PATCH] D73079: [LV] Fix predication for branches with matching true and false succs.

[Florian Hahn via Phabricator via llvm-commits]

fhahn marked an inline comment as done.
fhahn added inline comments.


================
Comment at: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:6732
 
   if (!BI->isConditional())
     return EdgeMaskCache[Edge] = SrcMask;
----------------
Ayal wrote:
> ```
> if (!BI->isConditional() || BI->getSuccessor(0) == BI->getSuccessor(1))
>   return EdgeMaskCache[Edge] = SrcMask;
> 
> ```
> ?
> 
> Best be cleaned up before LV, as it may misguide cost, but when both successors are the same the branch is essentially unconditional.
> if (!BI->isConditional() || BI->getSuccessor(0) == BI->getSuccessor(1))
>   return EdgeMaskCache[Edge] = SrcMask;
> ?

Yes that is even simpler! I wasn't aware that we already support potentially null masks elsewhere.

> 
> Best be cleaned up before LV, as it may misguide cost, but when both successors are the same the branch is essentially unconditional.

Agreed and I don't think such branches would ever hit this point in a real-world pipeline. 




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https://reviews.llvm.org/D73079