[Bug tree-optimization/85700] Spurious -Wstringop-truncation warning with strncat

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85700

--- Comment #4 from Martin Sebor <msebor at gcc dot gnu.org> ---
Author: msebor
Date: Mon Jun 25 20:33:28 2018
New Revision: 262110

URL: https://gcc.gnu.org/viewcvs?rev=262110&root=gcc&view=rev
Log:
PR tree-optimization/85700 - Spurious -Wstringop-truncation warning with
strncat

gcc/ChangeLog:

        PR tree-optimization/85700
        * gimple-fold.c (gimple_fold_builtin_strncat): Adjust comment.
        * tree-ssa-strlen.c (is_strlen_related_p): Handle integer subtraction.
        (maybe_diag_stxncpy_trunc): Distinguish strncat from strncpy.

gcc/testsuite/ChangeLog:

        PR tree-optimization/85700
        * gcc.dg/Wstringop-truncation-4.c: New test.


Added:
    trunk/gcc/testsuite/gcc.dg/Wstringop-truncation-4.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/gimple-fold.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-strlen.c