[Bug tree-optimization/71840] [7 Regression] internal compiler error: Segmentation fault in compute_avail

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71840

--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
I think this started with

commit e1bba98001be7ab89d5734ae0fdfe3996b4281a7
Author: rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Thu Jul 7 07:43:35 2016 +0000

    2016-07-07  Richard Biener  <rguenther@suse.de>

        * tree-ssa-pre.c: Include alias.h.
        (compute_avail): If we have multiple VN_REFERENCEs with the
        same hashtable entry adjust that to make it a valid replacement
        for all of them with respect to alignment and aliasing
        when doing insertion.
        * tree-ssa-sccvn.h (vn_reference_operands_for_lookup): Declare.
        * tree-ssa-sccvn.c (vn_reference_operands_for_lookup): New function.


    git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@238078
138bc75d-0d04-0410-961f-82ee72b054a4

(but doesn't look like a dup of PR71816).