[Bug c/79692] [7 Regression] -Wformat-overflow false positive with unknown width

["msebor at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79692

--- Comment #4 from Martin Sebor <msebor at gcc dot gnu.org> ---
Author: msebor
Date: Wed Mar  1 23:39:59 2017
New Revision: 245822

URL: https://gcc.gnu.org/viewcvs?rev=245822&root=gcc&view=rev
Log:
PR middle-end/79692 - [7 Regression] -Wformat-overflow false positive

gcc/ChangeLog:

        PR middle-end/79692
        * gimple-ssa-sprintf.c
        (directive::known_width_and_precision): New function.
        (format_integer): Use it.
        (get_mpfr_format_length): Consider the full range of precision
        when computing %g output with the # flag.  Set the likely byte
        count to 3 rather than 1 when precision is indeterminate.
        (format_floating): Correct the lower bound of precision.

gcc/testsuite/ChangeLog:

        PR middle-end/79692
        * gcc.dg/tree-ssa/builtin-sprintf-2.c: Add test cases.
        * gcc.dg/tree-ssa/builtin-sprintf-warn-10.c: Correct %#g.
        * gcc.dg/tree-ssa/builtin-sprintf-warn-15.c: New test.
        * gcc.dg/tree-ssa/builtin-snprintf-3.c: Ditto.


Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/builtin-snprintf-3.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-warn-15.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/gimple-ssa-sprintf.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-2.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-warn-10.c