i386: Optimize vpblendvb on inverted mask register to vpblendvb on swapping the order of operand 1 and operand 2. [PR target/99908]

-       vpcmpeqd        %ymm3, %ymm3, %ymm3
-       vpandn  %ymm3, %ymm2, %ymm2
-       vpblendvb       %ymm2, %ymm1, %ymm0, %ymm0
+       vpblendvb       %ymm2, %ymm0, %ymm1, %ymm0

gcc/ChangeLog:

	PR target/99908
	* config/i386/sse.md (<sse4_1_avx2>_pblendvb): Add
	splitters for pblendvb of NOT mask register.

gcc/testsuite/ChangeLog:

	PR target/99908
	* gcc.target/i386/avx2-pr99908.c: New test.
	* gcc.target/i386/sse4_1-pr99908.c: New test.

3 files changed, 77 insertions, 0 deletions

diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md
index 244fb13..49dda74 100644
--- a/gcc/config/i386/sse.md
+++ b/gcc/config/i386/sse.md
@@ -17734,6 +17734,35 @@
    (set_attr "btver2_decode" "vector,vector,vector")
    (set_attr "mode" "<sseinsnmode>")])
 
+(define_split
+  [(set (match_operand:VI1_AVX2 0 "register_operand")
+	(unspec:VI1_AVX2
+	  [(match_operand:VI1_AVX2 1 "vector_operand")
+	   (match_operand:VI1_AVX2 2 "register_operand")
+	   (not:VI1_AVX2 (match_operand:VI1_AVX2 3 "register_operand"))]
+	  UNSPEC_BLENDV))]
+  "TARGET_SSE4_1"
+  [(set (match_dup 0)
+	(unspec:VI1_AVX2
+	  [(match_dup 2) (match_dup 1) (match_dup 3)]
+	  UNSPEC_BLENDV))])
+
+(define_split
+  [(set (match_operand:VI1_AVX2 0 "register_operand")
+	(unspec:VI1_AVX2
+	  [(match_operand:VI1_AVX2 1 "vector_operand")
+	   (match_operand:VI1_AVX2 2 "register_operand")
+	   (subreg:VI1_AVX2 (not (match_operand 3 "register_operand")) 0)]
+	  UNSPEC_BLENDV))]
+  "TARGET_SSE4_1
+   && GET_MODE_CLASS (GET_MODE (operands[3])) == MODE_VECTOR_INT
+   && GET_MODE_SIZE (GET_MODE (operands[3])) == <MODE_SIZE>"
+  [(set (match_dup 0)
+	(unspec:VI1_AVX2
+	  [(match_dup 2) (match_dup 1) (match_dup 4)]
+	  UNSPEC_BLENDV))]
+  "operands[4] = gen_lowpart (<MODE>mode, operands[3]);")
+
 (define_insn_and_split "*<sse4_1_avx2>_pblendvb_lt"
   [(set (match_operand:VI1_AVX2 0 "register_operand" "=Yr,*x,x")
 	(unspec:VI1_AVX2
diff --git a/gcc/testsuite/gcc.target/i386/avx2-pr99908.c b/gcc/testsuite/gcc.target/i386/avx2-pr99908.c
new file mode 100644
index 0000000..2775f3b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/avx2-pr99908.c
@@ -0,0 +1,25 @@
+/* PR target/99908 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -mavx2 -masm=att" } */
+/* { dg-final { scan-assembler-times "\tvpblendvb\t" 2 } } */
+/* { dg-final { scan-assembler-not "\tvpcmpeq" } } */
+/* { dg-final { scan-assembler-not "\tvpandn" } } */
+
+#include <x86intrin.h>
+
+__m256i
+f1 (__m256i a, __m256i b, __m256i mask)
+{
+  return _mm256_blendv_epi8(a, b, 
+    _mm256_andnot_si256(mask, _mm256_set1_epi8(255)));
+}
+
+__m256i
+f2 (__v32qi x, __v32qi a, __v32qi b)
+{
+  x ^= (__v32qi) { -1, -1, -1, -1, -1, -1, -1, -1,
+		   -1, -1, -1, -1, -1, -1, -1, -1,
+		   -1, -1, -1, -1, -1, -1, -1, -1,
+		   -1, -1, -1, -1, -1, -1, -1, -1 };
+  return _mm256_blendv_epi8 ((__m256i) a, (__m256i) b, (__m256i) x);
+}
diff --git a/gcc/testsuite/gcc.target/i386/sse4_1-pr99908.c b/gcc/testsuite/gcc.target/i386/sse4_1-pr99908.c
new file mode 100644
index 0000000..c13e730
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/sse4_1-pr99908.c
@@ -0,0 +1,23 @@
+/* PR target/99908 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -msse4.1 -mno-avx -masm=att" } */
+/* { dg-final { scan-assembler-times "\tpblendvb\t" 2 } } */
+/* { dg-final { scan-assembler-not "\tpcmpeq" } } */
+/* { dg-final { scan-assembler-not "\tpandn" } } */
+
+#include <x86intrin.h>
+
+__m128i
+f1 (__m128i a, __m128i b, __m128i mask)
+{
+  return _mm_blendv_epi8(a, b, 
+    _mm_andnot_si128(mask, _mm_set1_epi8(255)));
+}
+
+__m128i
+f2 (__v16qi x, __v16qi a, __v16qi b)
+{
+  x ^= (__v16qi) { -1, -1, -1, -1, -1, -1, -1, -1,
+		   -1, -1, -1, -1, -1, -1, -1, -1 };
+  return _mm_blendv_epi8 ((__m128i) a, (__m128i) b, (__m128i) x);
+}