[Bug tree-optimization/87621] outer loop auto-vectorization fails for exponentiation code

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87621

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Fri Nov  9 10:53:31 2018
New Revision: 265959

URL: https://gcc.gnu.org/viewcvs?rev=265959&root=gcc&view=rev
Log:
2018-11-09  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/87621
        * tree-vect-loop.c (vectorizable_reduction): Handle reduction
        op with only phi inputs.
        * tree-ssa-loop-ch.c: Include tree-ssa-sccvn.h.
        (ch_base::copy_headers): Run CSE on copied loop headers.
        (pass_ch_vect::process_loop_p): Simplify.

        * g++.dg/vect/pr87621.cc: New testcase.

Added:
    trunk/gcc/testsuite/g++.dg/vect/pr87621.cc
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-loop-ch.c
    trunk/gcc/tree-vect-loop.c