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

[Sjoerd Meijer via Phabricator via llvm-commits]

SjoerdMeijer added a comment.

Caught up on all previous messages, and I believe missing in this patch is control over some of the decision making of this old and new behaviour. Rather than introducing yet another option, I liked @Ayal 's suggestion:

> value added to -prefer-predicate-over-epilog=x indicating the "strength" of the preference.

for which I will introduce these values/options:

- x = 1:  vectorize if we can't fail-fold,
- x = 2 :  don't vectorize if we can't tail-fold

I think this models the "strength" of the vector tail-folding preference.


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https://reviews.llvm.org/D79783