[PATCH] D79783: [LoopVectorize] Fallback to a scalar epilogue when TP fails

[Sjoerd Meijer via Phabricator via llvm-commits]

SjoerdMeijer added a comment.

Motivated by the discussion on the added test case, just a general remark about the description of this change:

> This patch teaches the vectorizer to fallback to a scalar epilogue when a tail-predication hint is found

Using "hint" here can be a bit ambigious. I think the complete story is that we always fall back to a scalar epilogue, regardless whether tail-folding was requested on the command-line, a loop hint, or the TTI hook. Thinking about this, it's probably worth mentioning this on the documentation or description of the -prefer-predicate-over-epilog option, and/or the general documentation of the vectorize_predicate pragma, for which there probably also needs to be a test case added, i.e. for all 3 cases how tail-folding can be requested, there need to be a test. Looks like 2 are covered already: the option, and the TTI hook.


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https://reviews.llvm.org/D79783