https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68785
David Binderman <dcb314 at hotmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |dcb314 at hotmail dot com --- Comment #14 from David Binderman <dcb314 at hotmail dot com> --- Interestingly, I ran the code in comment 8 through a valgrind version of recent gcc trunk, with the compiler flag -O2, and got this: ./gcc.dg/pr68785.c ==49861== Invalid read of size 1 ==49861== at 0xD9CDDD: count_nonzero_bytes(tree_node*, unsigned long, unsigned long, unsigned int*, bool*, bool*, bool*, vr_values const*, ssa_name_limit_t&) (tree-ssa-strlen.c:4891) ==49861== by 0xD9CF17: count_nonzero_bytes(tree_node*, unsigned long, unsigned long, unsigned int*, bool*, bool*, bool*, vr_values const*, ssa_name_limit_t&) (tree-ssa-strlen.c:4801) ==49861== by 0xDA19EE: count_nonzero_bytes (tree-ssa-strlen.c:4920) ==49861== by 0xDA19EE: handle_integral_assign(gimple_stmt_iterator*, bool*, vr_values const*) (tree-ssa-strlen.c:5547)