[Bug middle-end/68067] [4.9/5 Regression] Wrong constant folding

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68067

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Wed Oct 28 10:01:23 2015
New Revision: 229479

URL: https://gcc.gnu.org/viewcvs?rev=229479&root=gcc&view=rev
Log:
2015-10-28  Richard Biener  <rguent...@suse.de>

        PR middle-end/68067
        * fold-const.c (negate_expr_p): We cannot negate plus or minus
        if overflow is not wrapping.  Likewise multiplication unless
        one operand is constant and not power of two.
        (fold_negate_expr): Adjust accordingly.

        * gcc.dg/torture/pr68067-1.c: New testcase.
        * gcc.dg/torture/pr68067-2.c: Likewise.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr68067-1.c
    trunk/gcc/testsuite/gcc.dg/torture/pr68067-2.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/fold-const.c
    trunk/gcc/testsuite/ChangeLog