[Bug tree-optimization/65930] Reduction with sign-change not handled

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65930

--- Comment #21 from Rainer Orth <ro at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #19)
> Author: rguenth
> Date: Wed Oct 23 12:41:49 2019
> New Revision: 277322
> 
> URL: https://gcc.gnu.org/viewcvs?rev=277322&root=gcc&view=rev
> Log:
> 2019-10-23  Richard Biener  <rguenther@suse.de>
> 
> 	PR tree-optimization/65930
> 	* tree-vect-loop.c (check_reduction_path): Allow conversions
> 	that only change the sign.
> 	(vectorizable_reduction): Relax latch def stmts we handle further.
> 
> 	* gcc.dg/vect/vect-reduc-2char-big-array.c: Adjust.
> 	* gcc.dg/vect/vect-reduc-2char.c: Likewise.
> 	* gcc.dg/vect/vect-reduc-2short.c: Likewise.
> 	* gcc.dg/vect/vect-reduc-dot-s8b.c: Likewise.
> 	* gcc.dg/vect/vect-reduc-pattern-2c.c: Likewise.

This patch caused a couple of regressions on Solaris/SPARC (32 and 64-bit):

+FAIL: gcc.dg/vect/vect-reduc-2char-big-array.c -flto -ffat-lto-objects 
scan-tree-dump-times vect "vectorized 3 loops" 1
+FAIL: gcc.dg/vect/vect-reduc-2char-big-array.c scan-tree-dump-times vect
"vectorized 3 loops" 1
+FAIL: gcc.dg/vect/vect-reduc-2char.c -flto -ffat-lto-objects 
scan-tree-dump-times vect "vectorized 3 loops" 1
+FAIL: gcc.dg/vect/vect-reduc-2char.c scan-tree-dump-times vect "vectorized 3
loops" 1
+FAIL: gcc.dg/vect/vect-reduc-2short.c -flto -ffat-lto-objects 
scan-tree-dump-times vect "vectorized 3 loops" 1
+FAIL: gcc.dg/vect/vect-reduc-2short.c scan-tree-dump-times vect "vectorized 3
loops" 1
+FAIL: gcc.dg/vect/vect-reduc-dot-s8b.c -flto -ffat-lto-objects 
scan-tree-dump-times vect "vectorized 1 loops" 1
+FAIL: gcc.dg/vect/vect-reduc-dot-s8b.c scan-tree-dump-times vect "vectorized 1
loops" 1
+FAIL: gcc.dg/vect/vect-reduc-pattern-2c.c -flto -ffat-lto-objects 
scan-tree-dump-times vect "vectorized 1 loops" 1
+FAIL: gcc.dg/vect/vect-reduc-pattern-2c.c scan-tree-dump-times vect
"vectorized 1 loops" 1

I'm attaching the vect-reduc-2char-big-array.c dump as an example.