[Bug tree-optimization/92408] strlen(s) != 0 not folded into *s

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92408

--- Comment #7 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jeff Law <[email protected]>:

https://gcc.gnu.org/g:1649ee187dfdb89f52e6acf15525465f77b67a64

commit r17-2695-g1649ee187dfdb89f52e6acf15525465f77b67a64
Author: Ashley Chekhova <[email protected]>
Date:   Fri Jul 24 23:26:43 2026 -0600

    [PATCH v2] tree-optimization: Fix strlen(s) != 0 not folded into *s
[PR92408]

    Checks for strlen(s) == 0 could be rewritten as *s == 0 in the simple
    case, but in complex cases (such as those involving variable
    assignment), the optimization wouldn't be implemented. Fix this
    by moving it over to forwprop from fold-const. Although, since
    this currently only runs when PROP_last_full_fold is set, the
    original code is kept in as well.

    Bootstrapped and tested on x86_64-pc-linux-gnu

            PR tree-optimization/92408

    gcc/ChangeLog:

            * tree-ssa-forwprop.cc (optimize_strlen_comp): Rewrite
            strlen(s) == 0 as *s == 0 and strlen(s) != 0 as *s != 0.
            (simplify_builtin_call): Added call to optimize_strlen_comp.

    gcc/testsuite/ChangeLog:
            * gcc.dg/pr92408.c: New test.