[Bug debug/89463] debug information for iteractor of an empty loop is gone (at -O3)

[qrzhang at gatech dot edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89463

--- Comment #6 from Qirun Zhang <qrzhang at gatech dot edu> ---
As mentioned in my earlier comment, the revision should be between gcc-5 and
gcc-6.

Bisect points to r239357.


commit ec969ce4161538b561592a032eca6dcfaf513596
Author: rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Thu Aug 11 09:02:04 2016 +0000

    2016-08-11  Richard Biener  <rguenther@suse.de>

        PR tree-optimization/72772
        * cfgloopmanip.c (create_preheader): Use split_edge if there
        is a single loop entry, avoiding degenerate PHIs.

        * gcc.dg/graphite/pr35356-1.c: Adjust.
        * gcc.dg/tree-ssa/pr59597.c: Likewise.


    git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@239357
138bc75d-0d04-0410-961f-82ee72b054a4