[Bug tree-optimization/88315] SAD and DOT_PROD SLP reductions with initial value != 0 create wrong code

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88315

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Fri Aug 30 13:19:23 2019
New Revision: 275168

URL: https://gcc.gnu.org/viewcvs?rev=275168&root=gcc&view=rev
Log:
2019-08-30  Richard Biener  <rguenther@suse.de>

        Backport from mainline
        2019-01-07  Richard Sandiford  <richard.sandiford@arm.com>

        PR middle-end/88567
        * tree-vect-loop.c (get_initial_defs_for_reduction): Pass the
        output vector directly to duplicate_and_interleave instead of
        going through a temporary.  Postpone insertion of ctor_seq to
        the end of the loop.

        2018-12-04  Richard Biener  <rguenther@suse.de>

        PR tree-optimization/88315
        * tree-vect-loop.c (get_initial_defs_for_reduction): Simplify
        and fix initialization vector for SAD and DOT_PROD SLP reductions.

        * gcc.dg/vect/slp-reduc-sad.c: Adjust to provide non-trivial
        initial value.

Modified:
    branches/gcc-8-branch/gcc/ChangeLog
    branches/gcc-8-branch/gcc/testsuite/ChangeLog
    branches/gcc-8-branch/gcc/testsuite/gcc.dg/vect/slp-reduc-sad.c
    branches/gcc-8-branch/gcc/tree-vect-loop.c