https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105646
--- 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:a1cd4d52d6ef90b977fb2d80c1cf17f3efa5b01d commit r13-2926-ga1cd4d52d6ef90b977fb2d80c1cf17f3efa5b01d Author: Richard Biener <rguent...@suse.de> Date: Fri Aug 19 15:11:14 2022 +0200 tree-optimization/105646 - re-interpret always executed in uninit diag The following fixes PR105646, not diagnosing int f1(); int f3(){ auto const & a = f1(); bool v3{v3}; return a; } with optimization because the early uninit diagnostic pass only diagnoses always executed cases. The patch does this by re-interpreting what always executed means and choosing to ignore exceptional and abnormal control flow for this. At the same time it improves things as suggested in a comment - when the value-numbering run done without optimizing figures there's a fallthru path, consider blocks on it as always executed. PR tree-optimization/105646 * tree-ssa-uninit.cc (warn_uninitialized_vars): Pre-compute the set of fallthru reachable blocks from function entry and use that to determine wlims.always_executed. * g++.dg/uninit-pr105646.C: New testcase.