[PATCH] D71250: [LV] Create new vector loop preheader so it contains vectorizer generated code only.

[Renato Golin via Phabricator via llvm-commits]

rengolin added a comment.

This change introduces a number of new branches in the code. While not necessarily the hottest code, it may prove significant on short loops, especially nested loops. Without evidence in the form of benchmarks etc. it's hard to justify.

Furthermore, I'm not sure I agree with the statement that this makes the analysis somehow simpler. Do you have an explicit goal in mind?



================
Comment at: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:2680
+  // No trip count check needed for predicated vectorization.
+  if (Cost->foldTailByMasking())
+    return;
----------------
Are you sure this is semantically valid on all targets?


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  https://reviews.llvm.org/D71250/new/

https://reviews.llvm.org/D71250