https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97832
--- Comment #12 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:ce670e4faafb296d1f1a7828d20f8c8ba4686797 commit r12-1329-gce670e4faafb296d1f1a7828d20f8c8ba4686797 Author: Richard Biener <rguent...@suse.de> Date: Wed Nov 18 14:17:34 2020 +0100 tree-optimization/97832 - handle associatable chains in SLP discovery This makes SLP discovery handle associatable (including mixed plus/minus) chains better by swapping operands across the whole chain. To work this adds caching of the 'matches' lanes for failed SLP discovery attempts, thereby fixing a failed SLP discovery for the slp-pr98855.cc testcase which results in building an operand from scalars as expected. Unfortunately this makes us trip over the cost threshold so I'm XFAILing the testcase for now. For BB vectorization all this doesn't work because we have no way to distinguish good from bad associations as we eventually build operands from scalars and thus not fail in the classical sense. 2021-05-31 Richard Biener <rguent...@suse.de> PR tree-optimization/97832 * tree-vectorizer.h (_slp_tree::failed): New. * tree-vect-slp.c (_slp_tree::_slp_tree): Initialize failed member. (_slp_tree::~_slp_tree): Free failed. (vect_build_slp_tree): Retain failed nodes and record matches in them, copying that back out when running into a cached fail. Dump start and end of discovery. (dt_sort_cmp): New. (vect_build_slp_tree_2): Handle associatable chains together doing more aggressive operand swapping. * gcc.dg/vect/pr97832-1.c: New testcase. * gcc.dg/vect/pr97832-2.c: Likewise. * gcc.dg/vect/pr97832-3.c: Likewise. * g++.dg/vect/slp-pr98855.cc: XFAIL.
