[Bug tree-optimization/78476] snprintf(0, 0, ...) with known arguments not optimized away

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78476

--- Comment #3 from Martin Sebor <msebor at gcc dot gnu.org> ---
Author: msebor
Date: Thu Nov 24 22:45:18 2016
New Revision: 242854

URL: https://gcc.gnu.org/viewcvs?rev=242854&root=gcc&view=rev
Log:
PR tree-optimization/78476 - snprintf(0, 0, ...) with known arguments not
optimized away

gcc/testsuite/ChangeLog:

        PR tree-optimization/78476
        * gcc.dg/tree-ssa/builtin-sprintf-5.c: New test.

gcc/ChangeLog:

        PR tree-optimization/78476
        * gimple-ssa-sprintf.c (struct pass_sprintf_length::call_info):
        Add a member.
        (handle_gimple_call): Adjust signature.
        (try_substitute_return_value): Remove calls to bounded functions
        with zero buffer size whose result is known.
        (pass_sprintf_length::execute): Adjust call to handle_gimple_call.


Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-5.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/gimple-ssa-sprintf.c
    trunk/gcc/testsuite/ChangeLog