https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124868
--- Comment #8 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-13 branch has been updated by Richard Biener <[email protected]>: https://gcc.gnu.org/g:21bd348e140570a4caf4cc7fa8b5e906724583b6 commit r13-10368-g21bd348e140570a4caf4cc7fa8b5e906724583b6 Author: Richard Biener <[email protected]> Date: Mon Apr 13 13:18:00 2026 +0200 tree-optimization/124868 - path isolation wrong-code The path isolation code mishandles the case where in the same block there's both a return of a local variable and a dereference of zero but from different edges. In this case we re-use the produced block copy for both isolated paths, causing a trap on the path to the return of a non-local. The least intrusive change I came up with separates both causes and transforms, first isolating NULL dereferences and then isolating returns of non-NULL. This will skip the latter transform on paths which will now not return anyway. To avoid duplicate diagnostics the handle_return_addr_local_phi_arg only diagnoses cases in blocks dominated by the original block, not in copies which still need SSA update and thus are falsely visited. PR tree-optimization/124868 * gimple-ssa-isolate-paths.cc (handle_return_addr_local_phi_arg): Do not diagnose returns in blocks not dominated by the PHI. (find_implicit_erroneous_behavior): Do two sweeps over PHIs, first for NULL dereferences and then for local address returns. * gcc.dg/torture/pr124868.c: New testcase. (cherry picked from commit 935d483a80c7ab96d4e483e62a5c2cc138409ed3)
