Meinersbur added inline comments.
================ Comment at: docs/LanguageExtensions.rst:3068-3069 +There are loop hints that control transformations (e.g. vectorization, loop +unrolling) and there loop hints that set transformation options (e.g. +``vectorize_width``, ``unroll_count``). Pragmas setting transformation options ---------------- SjoerdMeijer wrote: > Meinersbur wrote: > > `vectorize_width` also "controls" a transformation. Is it that in our > > interpretation, `vectorize(enable)` overrides the profitability heuristic > > by taking out the "do not apply at all" option without setting any other > > option? > I think I need to think a little bit more about this: > > > Is it that in our interpretation, vectorize(enable) overrides the > > profitability heuristic by taking out the "do not apply at all" option > > without setting any other option? > > but I would answer this with "yes". But just checking, what exactly do you > mean with "do not apply at all option"? I unfortunately mixed two meanings of "option" here: 1. option as in optimization setting 2. option as in candidate to choose from. Let's take a look on the loop vectorizer. The profitability heuristic's job is too choose the "best" candidate out of the following list (independently of how LoopVectorize's heuristic is actually implemented; these might be decision made independently of each other, but as the user still sees one of the following outcomes): 0) no vectorization (the "do not apply at all" option/candidate) 1a) vec width=2 with epilogue 1b) vec width=2 without epilogue 2a) vec width=4 with epilogue 2b) vec width=4 without epilogue 3a) vec width=8 with epilogue 3b) vec width=8 without epilogue ... `vectorize(enable)` with remove 0) as a candidate. `vecorize(disable)` will remove all expect 0) as a candidate. The option/settings are `vectorize_width` and `vectorize_predicate` (and `interleave_count`). For instance `vectorize_width(4)` would remove 1) and 3)+ from the candidate list. `vectorize_predicate(enable)` takes any a) candidate from the list. What we were discussing was that these settings would remove 0) from the candidate list as well. CHANGES SINCE LAST ACTION https://reviews.llvm.org/D66199/new/ https://reviews.llvm.org/D66199 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
