https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101573
--- Comment #3 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:66030d68a7edfc9504a50469598e0707b8f787ce commit r12-2525-g66030d68a7edfc9504a50469598e0707b8f787ce Author: Richard Biener <rguent...@suse.de> Date: Thu Jul 22 12:26:16 2021 +0200 tree-optimization/101573 - improve uninit warning at -O0 We can improve uninit warnings from the early pass by looking at PHI arguments on fallthru edges that are uninitialized and have uses that are before a possible loop exit. This catches some cases earlier that we'd only warn in a more confusing way after early inlining as seen by testcase adjustments. It introduces FAIL: gcc.dg/uninit-23.c (test for excess errors) where we additionally warn gcc.dg/uninit-23.c:21:13: warning: 't4' is used uninitialized [-Wuninitialized] which I think is OK even if it's not obvious that the new warning is an improvement when you look at the obvious source. Somehow for all cases I never get the `'foo' was declared here` notes, I didn't dig why that happens but it's odd. 2021-07-22 Richard Biener <rguent...@suse.de> PR tree-optimization/101573 * tree-ssa-uninit.c (warn_uninit_phi_uses): New function looking at uninitialized PHI arg defs in some constrained cases. (warn_uninitialized_vars): Call it. (execute_early_warn_uninitialized): Calculate dominators. * gcc.dg/uninit-pr101573.c: New testcase. * gcc.dg/uninit-15-O0.c: Adjust. * gcc.dg/uninit-15.c: Likewise. * gcc.dg/uninit-23.c: Likewise. * c-c++-common/uninit-17.c: Likewise.
