[PATCH] D20639: SLPVectorizer: Move propagateMetadata to VectorUtils

[Justin Lebar via llvm-commits]

jlebar added inline comments.

================
Comment at: lib/Transforms/Vectorize/LoopVectorize.cpp:684
@@ -683,3 @@
-
-    To->setMetadata(Kind, M.second);
-  }
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jlebar wrote:
> Oh, I bet I see the problem.  There's a difference in behavior between this propagateMetadata and the new one.  This one ignores unknown metadata -- leaves it in place on "To".  The new one explicitly removes it.
Oh, that's not quite right -- in the event that you pass just one element for "from" to the new propagateMetadata, propagates *everything*.  The new propagateMetadata only removes unknown md if there are multiple "from"s.


http://reviews.llvm.org/D20639