https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68707
--- Comment #15 from Richard Biener <rguenth at gcc dot gnu.org> --- (In reply to alalaw01 from comment #13) > Hmmm, I realize a "definite" codegen improvement was maybe a bad choice of > wording. A "substantial" (albeit uncertain!) improvement, may have been more > accurate... > > However, yes it looks like we want that patch (indeed, it still helps even > when we up the cost of permute operations and drop the -fno-vect-cost-model) > - so thanks, Richard. We'll clean up the testisms in due course. > > In the longer term, is the issue here, that we aren't comparing costs of SLP > vs load-lanes, right? We merely compare the cost of whichever of those > vectorization strategies we favour, permutes et al, vs leaving it in scalar > code? Yes, at the moment cost comparison would be apples to oranges :( Note the commit was a revert - I accidentially committed the patch.
