https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105198
--- Comment #7 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:e5453bcc217ea4ac53a4ac277661d6ef0ccd425b commit r12-8059-ge5453bcc217ea4ac53a4ac277661d6ef0ccd425b Author: Richard Biener <rguent...@suse.de> Date: Fri Apr 8 13:13:29 2022 +0200 tree-optimization/105198 - wrong code with predictive commoning When predictive commoning looks for a looparound PHI it tries to match the entry value definition (a load) up with the appropriate member of the chain. But it fails to consider stmts clobbering the very same memory location inbetween the load and loop entry. In theory we could be more clever on must aliases that would be also picked up from a load (so not exactly stmt_kills_ref_p) and use the stored value from that if it is an exact match. But we currently have no way to propagate this information inside predcom. 2022-04-08 Richard Biener <rguent...@suse.de> PR tree-optimization/105198 * tree-predcom.cc (find_looparound_phi): Check whether the found memory location of the entry value is clobbered inbetween the value we want to use and loop entry. * gcc.dg/torture/pr105198.c: New testcase.
