https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102832
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Richard Biener <rgue...@gcc.gnu.org>: https://gcc.gnu.org/g:da2bf62d9e2a25f2d6a99176144c250b51fbdee7 commit r12-7127-gda2bf62d9e2a25f2d6a99176144c250b51fbdee7 Author: Richard Biener <rguent...@suse.de> Date: Wed Feb 9 10:55:18 2022 +0100 tree-optimization/104445 - check for vector extraction support This adds a missing check to epilogue reduction re-use, namely that we can do hi/lo extracts from the vector when demoting it to the epilogue vector size. I've chosen to add a can_vec_extract helper to optabs-query.h, in the future we might want to simplify the vectorizers life by handling vector-from-vector extraction via BIT_FIELD_REFs during RTL expansion via the mode punning when the vec_extract is not directly supported. I'm not 100% sure we can always do the punning of the vec_extract result to a vector mode of the same size, but then I'm also not sure how to check for that (the vectorizer doesn't in other places it does that at the moment, but I suppose we eventually just go through memory there)? 2022-02-09 Richard Biener <rguent...@suse.de> PR tree-optimization/104445 PR tree-optimization/102832 * optabs-query.h (can_vec_extract): New. * optabs-query.cc (can_vec_extract): Likewise. * tree-vect-loop.cc (vect_find_reusable_accumulator): Check we can extract a hi/lo part from the larger vector, rework check iteration from larger to smaller sizes. * gcc.dg/vect/pr104445.c: New testcase.
