[3/3][aarch64] Add support for vec_widen_shift pattern

[Richard Biener]

On Thu, 12 Nov 2020, Joel Hutton wrote:

> Hi all,
> 
> This patch adds support in the aarch64 backend for the vec_widen_shift vect-pattern and makes a minor mid-end fix to support it.
> 
> All 3 patches together bootstrapped and regression tested on aarch64.
> 
> Ok for stage 1?

diff --git a/gcc/tree-vect-stmts.c b/gcc/tree-vect-stmts.c
index
f12fd158b13656ee24022ec7e445c53444be6554..1f40b59c0560eec675af1d9a0e3e818d47
589de6 100644
--- a/gcc/tree-vect-stmts.c
+++ b/gcc/tree-vect-stmts.c
@@ -4934,8 +4934,13 @@ vectorizable_conversion (vec_info *vinfo,
                         &vec_oprnds1);
       if (code == WIDEN_LSHIFT_EXPR)
        {
-         vec_oprnds1.create (ncopies * ninputs);
-         for (i = 0; i < ncopies * ninputs; ++i)
+         int oprnds_size = ncopies * ninputs;
+         /* In the case of SLP ncopies = 1, so the size of vec_oprnds1 
here
+          * should be obtained by the the size of vec_oprnds0.  */

You should be able to always use vec_oprnds0.length ()

This hunk is OK with that change.

+         if (slp_node)
+           oprnds_size = vec_oprnds0.length ();
+         vec_oprnds1.create (oprnds_size);
+         for (i = 0; i < oprnds_size; ++i)
            vec_oprnds1.quick_push (op1);
        }
       /* Arguments are ready.  Create the new vector stmts.  */

> 
> gcc/ChangeLog:
> 
> 2020-11-12 ?Joel Hutton ?<joel.hutton@arm.com>
> 
> ? ? ? ? * config/aarch64/aarch64-simd.md: vec_widen_lshift_hi/lo<mode> patterns
> ? ? ? ? * tree-vect-stmts.c 
> ? ? ? ? (vectorizable_conversion): Fix for widen_lshift case
> 
> gcc/testsuite/ChangeLog:
> 
> 2020-11-12 ?Joel Hutton ?<joel.hutton@arm.com>
> 
> ? ? ? ? * gcc.target/aarch64/vect-widen-lshift.c: New test.
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imend