[Bug tree-optimization/71947] [6/7 Regression] x ^ y not folded to 0 if x == y by DOM

[law at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71947

--- Comment #12 from Jeffrey A. Law <law at gcc dot gnu.org> ---
Author: law
Date: Mon Oct 10 20:40:59 2016
New Revision: 240947

URL: https://gcc.gnu.org/viewcvs?rev=240947&root=gcc&view=rev
Log:
        PR tree-optimization/71947
        * tree-ssa-dom.c (cprop_into_stmt): Avoid replacing A with B, then
        B with A within a single statement.

        PR tree-optimization/71947
        * gcc.dg/tree-ssa/pr71947-1.c: New test.
        * gcc.dg/tree-ssa/pr71947-2.c: New test.
        * gcc.dg/tree-ssa/pr71947-3.c: New test.
        * gcc.dg/tree-ssa/pr71947-4.c: New test.
        * gcc.dg/tree-ssa/pr71947-5.c: New test.
        * gcc.dg/tree-ssa/pr71947-6.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr71947-1.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr71947-2.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr71947-3.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr71947-4.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr71947-5.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr71947-6.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-dom.c