https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115152
--- Comment #11 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-13 branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:53bc98f5355ada17d1629a2d0e96aebd397780c6 commit r13-8792-g53bc98f5355ada17d1629a2d0e96aebd397780c6 Author: Jakub Jelinek <ja...@redhat.com> Date: Wed May 22 09:13:50 2024 +0200 strlen: Fix up !si->full_string_p handling in count_nonzero_bytes_addr [PR115152] The following testcase is miscompiled because strlen_pass::count_nonzero_bytes_addr doesn't handle correctly the !si->full_string_p case. If si->full_string_p, it correctly computes minlen and maxlen as minimum and maximum length of the '\0' terminated stgring and clears *nulterm (ie. makes sure !full_string_p in the ultimate caller) if minlen is equal or larger than nbytes and so '\0' isn't guaranteed to be among those bytes. But in the !si->full_string_p case, all we know is that there are [minlen,maxlen] non-zero bytes followed by unknown bytes, so effectively the maxlen is infinite (but caller cares about only the first nbytes bytes) and furthermore, we never know if there is any '\0' char among those, so *nulterm needs to be always cleared. 2024-05-22 Jakub Jelinek <ja...@redhat.com> PR tree-optimization/115152 * tree-ssa-strlen.cc (strlen_pass::count_nonzero_bytes_addr): If !si->full_string_p, clear *nulterm and set maxlen to nbytes. * gcc.dg/pr115152.c: New test. (cherry picked from commit dbc9b45a3c2468ad134b3a9bd4961f7ae6bc1e67)
