[Bug middle-end/67662] -fsanitize=undefined cries wolf for X - 1 + X when X is 2**30

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67662

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Wed Nov 18 12:23:14 2015
New Revision: 230542

URL: https://gcc.gnu.org/viewcvs?rev=230542&root=gcc&view=rev
Log:
2015-11-18  Richard Biener  <rguenther@suse.de>

        Backport from mainline
        2015-10-28  Richard Biener  <rguenther@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.

        2015-10-26  Richard Biener  <rguenther@suse.de>
                Dominik Vogt  <vogt@linux.vnet.ibm.com>

        PR middle-end/67443
        * alias.c (ao_ref_from_mem): Remove promoted subreg handling.
        Properly prune ref->ref for accesses outside of ref.

        * gcc.target/s390/pr67443.c: New testcase.

        2015-10-20  Richard Biener  <rguenther@suse.de>

        PR tree-optimization/68017
        * tree-tailcall.c (eliminate_tail_call): Remove stmts backwards.

        * gcc.dg/torture/pr68017.c: New testcase.

        2015-09-23   Richard Biener  <rguenther@suse.de>

        PR middle-end/67662
        * fold-const.c (fold_binary_loc): Do not reassociate two vars with
        undefined overflow unless they will cancel out.

        * gcc.dg/ubsan/pr67662.c: New testcase.

Added:
    branches/gcc-5-branch/gcc/testsuite/gcc.dg/torture/pr68017.c
    branches/gcc-5-branch/gcc/testsuite/gcc.dg/torture/pr68067-1.c
    branches/gcc-5-branch/gcc/testsuite/gcc.dg/torture/pr68067-2.c
    branches/gcc-5-branch/gcc/testsuite/gcc.dg/ubsan/pr67662.c
    branches/gcc-5-branch/gcc/testsuite/gcc.target/s390/pr67443.c
Modified:
    branches/gcc-5-branch/gcc/ChangeLog
    branches/gcc-5-branch/gcc/alias.c
    branches/gcc-5-branch/gcc/fold-const.c
    branches/gcc-5-branch/gcc/testsuite/ChangeLog
    branches/gcc-5-branch/gcc/tree-tailcall.c