@@ -26778,11 +26778,14 @@ (define_insn "<mask_codefor>avx512dq_broadcast<mode><mask_name>_1"
(set_attr "prefix" "evex")
(set_attr "mode" "<sseinsnmode>")])
+;; Use unspec to prevent rtl optimizer to optimize zero_extend + vec_duplicate
+;; to pbroadcastm, there could be an extra kmov after RA.
(define_insn "avx512cd_maskb_vec_dup<mode>"
[(set (match_operand:VI8_AVX512VL 0 "register_operand" "=v")
(vec_duplicate:VI8_AVX512VL
(zero_extend:DI
- (match_operand:QI 1 "register_operand" "k"))))]
+ (match_operand:QI 1 "register_operand" "k"))))
+ (unspec [(const_int 0)] UNSPEC_MASKOP)]
"TARGET_AVX512CD"
"vpbroadcastmb2q\t{%1, %0|%0, %1}"
[(set_attr "type" "mskmov")
@@ -26793,7 +26796,8 @@ (define_insn "avx512cd_maskw_vec_dup<mode>"
[(set (match_operand:VI4_AVX512VL 0 "register_operand" "=v")
(vec_duplicate:VI4_AVX512VL
(zero_extend:SI
- (match_operand:HI 1 "register_operand" "k"))))]
+ (match_operand:HI 1 "register_operand" "k"))))
+ (unspec [(const_int 0)] UNSPEC_MASKOP)]
"TARGET_AVX512CD"
"vpbroadcastmw2d\t{%1, %0|%0, %1}"
[(set_attr "type" "mskmov")
new file mode 100644
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -march=cascadelake --param vect-partial-vector-usage=2" } */
+/* { dg-final { scan-assembler-not "vpbroadcastm" } } */
+
+double a[1024], b[1024];
+
+void foo (int n)
+{
+ for (int i = 0; i < n; ++i)
+ a[i] = b[i] * 3.;
+}