[PATCH] D114087: [SLP]Improve registering and merging of compatible shuffles.

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


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Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:6807
+        return false;
+    // Check if the second instruction is more defined than the first one.
+    NewMask.assign(SI2->getShuffleMask().begin(), SI2->getShuffleMask().end());
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Add a comment about keep track of the terminating (trailing?) undefmaskelems


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Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:6815
+      else
+        LastUndefsCnt = 0;
+      if (NewMask[I] != UndefMaskElem && SM1[I] != UndefMaskElem &&
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ABataev wrote:
> RKSimon wrote:
> > I don't understand - why do you reset LastUndefsCnt here?
> `LastUndefsCnt` is the number of terminating undefmaskelems, that's why I reset it each time we ran into non-undef mask elem.
Got it - thanks.


Repository:
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  https://reviews.llvm.org/D114087/new/

https://reviews.llvm.org/D114087