[Bug middle-end/56917] -ftrapv detects a overflow wrongly.

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56917

--- Comment #7 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Author: mpolacek
Date: Wed Mar 11 10:37:38 2015
New Revision: 221346

URL: https://gcc.gnu.org/viewcvs?rev=221346&root=gcc&view=rev
Log:
    Backported from mainline
    2014-12-04  Marek Polacek  <polacek@redhat.com>

    PR middle-end/56917
    * fold-const.c (fold_unary_loc): Perform the negation in A's type
    when transforming ~ (A - 1) or ~ (A + -1) to -A.

    * c-c++-common/ubsan/pr56917.c: New test.

Added:
    branches/gcc-4_9-branch/gcc/testsuite/c-c++-common/ubsan/pr56917.c
Modified:
    branches/gcc-4_9-branch/gcc/ChangeLog
    branches/gcc-4_9-branch/gcc/fold-const.c
    branches/gcc-4_9-branch/gcc/testsuite/ChangeLog