https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99412
--- Comment #5 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:b073f2b098ba7819450d6c14a0fb96cb1c09f242 commit r13-5122-gb073f2b098ba7819450d6c14a0fb96cb1c09f242 Author: Richard Biener <rguent...@suse.de> Date: Thu Jan 12 11:18:22 2023 +0100 tree-optimization/99412 - reassoc and reduction chains With -ffast-math we end up associating reduction chains and break them - this is because of old code that tries to rectify reductions into a shape likened by the vectorizer. Nowadays the rank compute produces correct association for reduction chains and the vectorizer has robust support to fall back to a regular reductions (via reduction path) when it turns out to be not a proper reduction chain. So this patch removes the special code in reassoc which makes the TSVC s352 vectorized with -Ofast (it is already without -ffast-math). PR tree-optimization/99412 * tree-ssa-reassoc.cc (is_phi_for_stmt): Remove. (swap_ops_for_binary_stmt): Remove reduction handling. (rewrite_expr_tree_parallel): Adjust. (reassociate_bb): Likewise. * tree-parloops.cc (build_new_reduction): Handle MINUS_EXPR. * gcc.dg/vect/pr99412.c: New testcase. * gcc.dg/tree-ssa/reassoc-47.c: Adjust comment. * gcc.dg/tree-ssa/reassoc-48.c: Remove.
