[PATCH] D103458: [SLP]Improve gathering of scalar elements.

[Alexey Bataev via Phabricator via llvm-commits]

ABataev added inline comments.


================
Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:4841
+    // No need to insert undefs elements - exit.
+    if (isa<UndefValue>(V))
+      return Vec;
----------------
Carrot wrote:
> The problem is here.
> 
> An undef value can be a correct value. But a poison always means something is wrong. In line 4866 you created a poison value as default, an undef should overwrite the default poison value.
> 
Modified the reproducer a bit, after this Alive detected the problem in the transformation. Will post the fix soon, thanks!


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D103458/new/

https://reviews.llvm.org/D103458