[PATCH] [x86] Add UNSPEC_MASKOP to vpbroadcastm pattern.

[liuhongt <hongtao.liu@intel.com>]

Prevent rtl optimization of vec_duplicate + zero_extend to
vpbroadcastm since there could be an extra kmov after RA.

Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}
Ready to push to trunk.

gcc/ChangeLog:

	PR target/110788
	* config/i386/sse.md (avx512cd_maskb_vec_dup<mode>): Add
	UNSPEC_MASKOP.
	(avx512cd_maskw_vec_dup<mode>: Ditto.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/pr110788.c: New test.
---
 gcc/config/i386/sse.md                   |  8 ++++++--
 gcc/testsuite/gcc.target/i386/pr110788.c | 11 +++++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr110788.c

diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md
index 35fd66ed4aa..51961bbfc0b 100644
--- a/gcc/config/i386/sse.md
+++ b/gcc/config/i386/sse.md
@@ -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")
diff --git a/gcc/testsuite/gcc.target/i386/pr110788.c b/gcc/testsuite/gcc.target/i386/pr110788.c
new file mode 100644
index 00000000000..4cf1676ccb6
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr110788.c
@@ -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.;
+}
-- 
2.39.1.388.g2fc9e9ca3c