[PATCH] D65776: [Clang] Pragma vectorize_predicate implies vectorize

[Michael Kruse via Phabricator via cfe-commits]

Meinersbur added a comment.

Mmmh, I would have expected this to work the same way as `vectorize_width`. According to the docs:

> The following example implicitly enables vectorization and interleaving by specifying a vector width and interleaving count:
>  `#pragma clang loop vectorize_width(2) interleave_count(2)`
>  `for(...) {`
>  ` ...`
>  `}`

However, `vectorize_width` does not automatically set `llvm.loop.vectorize.enable`. Neither does `llvm.loop.vectorize.width` > 1 imply `LoopVectorizeHints::getForce()`. At some places they are checked together, such as `LoopVectorizeHints::allowReordering()`. Other places, notably `LoopVectorizationCostModel::selectVectorizationFactor()`, only queries `getForce()`. That is, `vectorize_width(2)` does not implicitly force vectorization in practice.


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https://reviews.llvm.org/D65776