[Bug middle-end/78622] [7 Regression] -Wformat-length/-fprintf-return-value incorrect with overflow/wrapping

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78622

--- Comment #3 from Martin Sebor <msebor at gcc dot gnu.org> ---
Author: msebor
Date: Mon Dec 12 21:56:22 2016
New Revision: 243582

URL: https://gcc.gnu.org/viewcvs?rev=243582&root=gcc&view=rev
Log:
PR middle-end/78622 - -Wformat-length/-fprintf-return-value incorrect with
overflow/wrapping

gcc/ChangeLog:

        PR middle-end/78622
        PR middle-end78606
        * gimple-ssa-sprintf.c (min_bytes_remaining): Use res.knownrange
        rather than res.bounded.
        (get_width_and_precision): Set precision to -1 when negative.
        (adjust_range_for_overflow): New function.
        (format_integer): Correct the handling of the space, plus, and pound
        flags, and the special case of zero precision.
        Always set res.bounded to true unless either precision or width
        is specified and unknown.
        Call adjust_range_for_overflow.
        Avoid use zero as the shortest value when precision is specified
        but unknown.
        (format_directive): Remove vestigial quoting.  Always inform of
        argument value or range when it's available.
        (add_bytes): Correct the computation of boundrange used to
        decide whether a warning is of a "maybe" or "defnitely" kind.

gcc/testsuite/ChangeLog:

        PR middle-end/78622
        PR middle-end78606
        * gcc.c-torture/execute/pr78622.c: New test.
        * gcc.dg/tree-ssa/builtin-sprintf-2.c: Remove "benign" undefined
        behavior inadvertently introduced in a previous commit.  Tighten
        up final checking.
        * gcc.dg/tree-ssa/builtin-sprintf-5.c: Rename macros for clarity.
        Add test cases.
        * gcc.dg/tree-ssa/builtin-sprintf-6.c: Add test cases.
        * gcc.dg/tree-ssa/builtin-sprintf-warn-1.c: Same.
        * gcc.dg/tree-ssa/builtin-sprintf-warn-2.c: Same.
        * gcc.dg/tree-ssa/builtin-sprintf-warn-3.c: Same.
        * gcc.dg/tree-ssa/builtin-sprintf-warn-5.c: Same.
        * gcc.dg/tree-ssa/builtin-sprintf-warn-6.c: Remove xfails and
        add a final optimization check.
        * gcc.dg/tree-ssa/builtin-sprintf.c: Add test cases.
        * gcc.dg/tree-ssa/pr78622.c: New test.


Added:
    trunk/gcc/testsuite/gcc.c-torture/execute/pr78622.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr78622.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-5.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-6.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-warn-1.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-warn-2.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-warn-3.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf-warn-6.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/builtin-sprintf.c