[Bug tree-optimization/68240] [6 Regression] compilation hangs on valid code at -O1 and above on x86_64-linux-gnu

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68240

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Tue Nov 10 10:14:02 2015
New Revision: 230095

URL: https://gcc.gnu.org/viewcvs?rev=230095&root=gcc&view=rev
Log:
2015-11-10  Richard Biener  <rguenther@suse.de>

        PR tree-optimization/68240
        * tree-ssa-sccvn.c (cond_stmts_equal_p): Handle commutative compares
        properly.
        (visit_phi): For PHIs with just a single executable edge
        take its value directly.
        (expressions_equal_p): Handle VN_TOP properly.

        * gcc.dg/torture/pr68240.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr68240.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-sccvn.c