[Bug tree-optimization/90316] [8/9 Regression] large compile time increase in opt / alias stmt walking for Go example

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90316

--- Comment #17 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Tue May  7 13:03:19 2019
New Revision: 270944

URL: https://gcc.gnu.org/viewcvs?rev=270944&root=gcc&view=rev
Log:
2019-05-07  Richard Biener  <rguenther@suse.de>

        PR tree-optimization/90316
        * tree-ssa-pre.c (translate_vuse_through_block): When
        same_valid is NULL do not bother to search for a virtual
        PHI continuation.
        (phi_translate_1): When operands changed we cannot keep
        the same value-number so do not bother to ask whether
        that's possible from translate_vuse_through_block.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-ssa-pre.c