https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107839
--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-12 branch has been updated by Richard Biener <rgue...@gcc.gnu.org>: https://gcc.gnu.org/g:812847a9d12c0b65695cbe1a23959b69a7e62355 commit r12-8977-g812847a9d12c0b65695cbe1a23959b69a7e62355 Author: Richard Biener <rguent...@suse.de> Date: Fri Dec 2 14:52:20 2022 +0100 tree-optimization/107833 - invariant motion of uninit uses The following fixes a wrong-code bug caused by loop invariant motion hoisting an expression using an uninitialized value outside of its controlling condition causing IVOPTs to use that to rewrite a defined value. PR107839 is a similar case involving a bogus uninit diagnostic. PR tree-optimization/107833 PR tree-optimization/107839 * cfghooks.cc: Include tree.h. * tree-ssa-loop-im.cc (movement_possibility): Wrap and make stmts using any ssa_name_maybe_undef_p operand to preserve execution. (loop_invariant_motion_in_fun): Call mark_ssa_maybe_undefs to init maybe-undefined status. * tree-ssa-loop-ivopts.cc (ssa_name_maybe_undef_p, ssa_name_set_maybe_undef, ssa_name_any_use_dominates_bb_p, mark_ssa_maybe_undefs): Move ... * tree-ssa.cc: ... here. * tree-ssa.h (ssa_name_any_use_dominates_bb_p, mark_ssa_maybe_undefs): Declare. (ssa_name_maybe_undef_p, ssa_name_set_maybe_undef): Define. * gcc.dg/torture/pr107833.c: New testcase. * gcc.dg/uninit-pr107839.c: Likewise. (cherry picked from commit 44c8402d35160515b3c09fd2bc239587e0c32a2b)
