[Bug tree-optimization/89789] [9 Regression] Compile time hog during RPO VN

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89789

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Mon Mar 25 13:53:50 2019
New Revision: 269917

URL: https://gcc.gnu.org/viewcvs?rev=269917&root=gcc&view=rev
Log:
2019-03-25  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/89789
        * tree-ssa-sccvn.c (set_ssa_val_to): Do not allow lattice
        changes from non-undefined back to undefined.

        * gcc.dg/torture/pr89789.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr89789.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-sccvn.c