[Bug tree-optimization/91996] fold non-constant strlen relational expressions

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91996

--- Comment #3 from Martin Sebor <msebor at gcc dot gnu.org> ---
Author: msebor
Date: Wed Oct 16 17:18:57 2019
New Revision: 277076

URL: https://gcc.gnu.org/viewcvs?rev=277076&root=gcc&view=rev
Log:
PR tree-optimization/91996 - fold non-constant strlen relational expressions

gcc/testsuite/ChangeLog:

        PR tree-optimization/91996
        * gcc.dg/strlenopt-80.c: New test.
        * gcc.dg/strlenopt-81.c: New test.

gcc/ChangeLog:

        PR tree-optimization/91996
        * tree-ssa-strlen.c (maybe_warn_pointless_strcmp): Improve location
        information.
        (compare_nonzero_chars): Add an overload.
        (count_nonzero_bytes): Add an argument.  Call overload above.
        Handle non-constant lengths in some range.
        (handle_store): Add an argument.
        (check_and_optimize_stmt): Pass an argument to handle_store.


Added:
    trunk/gcc/testsuite/gcc.dg/strlenopt-80.c
    trunk/gcc/testsuite/gcc.dg/strlenopt-81.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-strlen.c