[PATCH] [i386]Add combine splitter to transform pxor/pcmpeqb/pmovmskb/cmp 0xffff to ptest.

[Haochen Jiang via Gcc-patches]

Hi all,

This patch aims to add a combine splitter to transform 
pxor/pcmpeqb/pmovmskb/cmp 0xffff to ptest.

Regtested on x86_64-pc-linux-gnu. Ok for trunk?

BRs,
Haochen

gcc/ChangeLog:

        PR target/104371
        * config/i386/sse.md: Add new define_mode_attr and define_split.

gcc/testsuite/ChangeLog:

        PR target/104371
        * gcc.target/i386/pr104371-1.c: New test.
        * gcc.target/i386/pr104371-2.c: Ditto.
---
 gcc/config/i386/sse.md                     | 19 +++++++++++++++++++
 gcc/testsuite/gcc.target/i386/pr104371-1.c | 14 ++++++++++++++
 gcc/testsuite/gcc.target/i386/pr104371-2.c | 14 ++++++++++++++
 3 files changed, 47 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr104371-1.c
 create mode 100755 gcc/testsuite/gcc.target/i386/pr104371-2.c

diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md
index 7b791def542..71afda73c8f 100644
--- a/gcc/config/i386/sse.md
+++ b/gcc/config/i386/sse.md
@@ -20083,6 +20083,25 @@
    (set_attr "prefix" "maybe_vex")
    (set_attr "mode" "SI")])
 
+;; Optimize pxor/pcmpeqb/pmovmskb/cmp 0xffff to ptest.
+(define_mode_attr vi1avx2const
+  [(V32QI "0xffffffff") (V16QI "0xffff")])
+
+(define_split
+  [(set (reg:CCZ FLAGS_REG)
+       (compare:CCZ (unspec:SI
+                       [(eq:VI1_AVX2
+                           (match_operand:VI1_AVX2 0 "vector_operand")
+                           (match_operand:VI1_AVX2 1 "const0_operand"))]
+                   UNSPEC_MOVMSK)
+                (match_operand 2 "const_int_operand")))]
+  "TARGET_SSE4_1 && ix86_match_ccmode (insn, CCmode)
+  && (INTVAL (operands[2]) == (int) (<vi1avx2const>))"
+  [(set (reg:CC FLAGS_REG)
+       (unspec:CC [(match_dup 0)
+                   (match_dup 0)]
+                  UNSPEC_PTEST))])
+
 (define_expand "sse2_maskmovdqu"
   [(set (match_operand:V16QI 0 "memory_operand")
        (unspec:V16QI [(match_operand:V16QI 1 "register_operand")
diff --git a/gcc/testsuite/gcc.target/i386/pr104371-1.c 
b/gcc/testsuite/gcc.target/i386/pr104371-1.c
new file mode 100644
index 00000000000..df7c0b074e3
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr104371-1.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -msse4" } */
+/* { dg-final { scan-assembler "ptest\[ \\t\]" } } */
+/* { dg-final { scan-assembler-not "pxor\[ \\t\]" } } */
+/* { dg-final { scan-assembler-not "pcmpeqb\[ \\t\]" } } */
+/* { dg-final { scan-assembler-not "pmovmskb\[ \\t\]" } } */
+
+#include <smmintrin.h>
+#include <stdbool.h>
+
+bool is_zero(__m128i x)
+{
+  return _mm_movemask_epi8(_mm_cmpeq_epi8(x, _mm_setzero_si128())) == 0xffff;
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr104371-2.c 
b/gcc/testsuite/gcc.target/i386/pr104371-2.c
new file mode 100755
index 00000000000..f0d0afd5897
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr104371-2.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mavx2" } */
+/* { dg-final { scan-assembler "vptest\[ \\t\]" } } */
+/* { dg-final { scan-assembler-not "vpxor\[ \\t\]" } } */
+/* { dg-final { scan-assembler-not "vpcmpeqb\[ \\t\]" } } */
+/* { dg-final { scan-assembler-not "vpmovmskb\[ \\t\]" } } */
+
+#include <immintrin.h>
+#include <stdbool.h>
+
+bool is_zero256(__m256i x)
+{
+  return _mm256_movemask_epi8(_mm256_cmpeq_epi8(x, _mm256_setzero_si256())) == 
0xffffffff;
+}
-- 
2.18.1