https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102155
--- Comment #1 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:f482bf2af86990329b4df660f8c1eb9e094de9f9 commit r12-3307-gf482bf2af86990329b4df660f8c1eb9e094de9f9 Author: Richard Biener <rguent...@suse.de> Date: Wed Sep 1 09:51:45 2021 +0200 tree-optimization/102155 - fix LIM fill_always_executed_in CFG walk This fixes the CFG walk order of fill_always_executed_in to use RPO oder rather than the dominator based order computed by get_loop_body_in_dom_order. That fixes correctness issues with unordered dominator children. The RPO order computed by rev_post_order_and_mark_dfs_back_seme in its for-iteration mode is a good match for the algorithm. 2021-09-01 Richard Biener <rguent...@suse.de> PR tree-optimization/102155 * tree-ssa-loop-im.c (fill_always_executed_in_1): Iterate over a part of the RPO array and do not recurse here. Dump blocks marked as always executed. (fill_always_executed_in): Walk over the RPO array and process loops whose header we run into. (loop_invariant_motion_in_fun): Compute the first RPO using rev_post_order_and_mark_dfs_back_seme in iteration order and pass that to fill_always_executed_in.