[gcc r14-1868] x86/AVX512: use VMOVDDUP for broadcast to V2DF

[gcc r14-1868] x86/AVX512: use VMOVDDUP for broadcast to V2DF

[Jan Beulich]

https://gcc.gnu.org/g:a4df0ce78d6f1beee5d2ef53e2a1a9f3fc377100

commit r14-1868-ga4df0ce78d6f1beee5d2ef53e2a1a9f3fc377100
Author: Jan Beulich <jbeulich@suse.com>
Date:   Thu Jun 15 10:52:35 2023 +0200

    x86/AVX512: use VMOVDDUP for broadcast to V2DF
    
    Like is already the case for the AVX/AVX2 form, VMOVDDUP - acting on
    double precision floating values - is more appropriate to use here, and
    it can also result in shorter insn encodings when source is memory or
    %xmm0...%xmm7, and no masking is applied (in allowing a 2-byte VEX
    prefix then instead of a 3-byte one).
    
    gcc/
    
            * config/i386/sse.md (<avx512>_vec_dup<mode><mask_name>): Use
            vmovddup.

Diff:
---
 gcc/config/i386/sse.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md
index a0824ef2350..70d7410f7a9 100644
--- a/gcc/config/i386/sse.md
+++ b/gcc/config/i386/sse.md
@@ -25922,9 +25922,9 @@
   "TARGET_AVX512F"
 {
   /*  There is no DF broadcast (in AVX-512*) to 128b register.
-      Mimic it with integer variant.  */
+      Mimic it with vmovddup, just like vec_dupv2df<mask_name> does.  */
   if (<MODE>mode == V2DFmode)
-    return "vpbroadcastq\t{%1, %0<mask_operand2>|%0<mask_operand2>, %q1}";
+    return "vmovddup\t{%1, %0<mask_operand2>|%0<mask_operand2>, %q1}";
 
   return "v<sseintprefix>broadcast<bcstscalarsuff>\t{%1, %0<mask_operand2>|%0<mask_operand2>, %<iptr>1}";
 }