[Bug middle-end/81705] [8 Regression] UBSAN: yet another false positive

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81705

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Fri Aug  4 10:33:39 2017
New Revision: 250866

URL: https://gcc.gnu.org/viewcvs?rev=250866&root=gcc&view=rev
Log:
2017-08-04  Richard Biener  <rguenther@suse.de>

        PR middle-end/81705
        * fold-const.c (fold_binary_loc): Properly restrict
        minus_var0 && minus_var1 case when associating undefined overflow
        entities.

        * c-c++-common/ubsan/pr81705.c: New testcase.

Added:
    trunk/gcc/testsuite/c-c++-common/ubsan/pr81705.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/fold-const.c
    trunk/gcc/testsuite/ChangeLog