LoongArch: Opitmize the cost of vec_construct.

When analyzing 525 on LoongArch architecture, it was found that the
for loop of hotspot function x264_pixel_satd_8x4 could not be quantized
256-bit due to the cost of vec_construct setting. After re-adjusting
vec_construct, the performance of 525 program was improved by 16.57%.
It was found that this function can be vectorized on the aarch64 and
x86 architectures, see [PR98138].

Co-Authored-By: Deng Jianbo <dengjianbo@loongson.cn>.
gcc/ChangeLog:

	* config/loongarch/loongarch.cc
	(loongarch_builtin_vectorization_cost): Modify the
	construction cost of the vec_construct vector.

gcc/testsuite/ChangeLog:

	* gcc.target/loongarch/vect-slp-two-operator.c: New test.

diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
index d506354c48a0f5ead877b9475a2445f4e72d2959..24c19031026add0be65f84041c93706b4ba6f156 100644 (file)
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -4127,10 +4127,10 @@ loongarch_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost,
 
       case vec_construct:
        elements = TYPE_VECTOR_SUBPARTS (vectype);
-       if (ISA_HAS_LASX)
-         return elements + 1;
+       if (LASX_SUPPORTED_MODE_P (mode) && !LSX_SUPPORTED_MODE_P (mode))
+         return elements / 2 + 3;
        else
-         return elements;
+         return elements / 2 + 1;
 
       default:
        gcc_unreachable ();

diff --git a/gcc/testsuite/gcc.target/loongarch/vect-slp-two-operator.c b/gcc/testsuite/gcc.target/loongarch/vect-slp-two-operator.c
new file mode 100644 (file)
index 0000000..43b4675
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/vect-slp-two-operator.c
@@ -0,0 +1,38 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mlasx -ftree-vectorize -fdump-tree-vect -fdump-tree-vect-details" } */
+
+typedef unsigned char uint8_t;
+typedef unsigned int uint32_t;
+
+#define HADAMARD4(d0, d1, d2, d3, s0, s1, s2, s3)                             \
+  {                                                                           \
+    int t0 = s0 + s1;                                                         \
+    int t1 = s0 - s1;                                                         \
+    int t2 = s2 + s3;                                                         \
+    int t3 = s2 - s3;                                                         \
+    d0 = t0 + t2;                                                             \
+    d1 = t1 + t3;                                                             \
+    d2 = t0 - t2;                                                             \
+    d3 = t1 - t3;                                                             \
+  }
+
+void sink (uint32_t tmp[4][4]);
+
+void
+x264_pixel_satd_8x4 (uint8_t *pix1, int i_pix1, uint8_t *pix2, int i_pix2)
+{
+  uint32_t tmp[4][4];
+  int sum = 0;
+  for (int i = 0; i < 4; i++, pix1 += i_pix1, pix2 += i_pix2)
+    {
+      uint32_t a0 = (pix1[0] - pix2[0]) + ((pix1[4] - pix2[4]) << 16);
+      uint32_t a1 = (pix1[1] - pix2[1]) + ((pix1[5] - pix2[5]) << 16);
+      uint32_t a2 = (pix1[2] - pix2[2]) + ((pix1[6] - pix2[6]) << 16);
+      uint32_t a3 = (pix1[3] - pix2[3]) + ((pix1[7] - pix2[7]) << 16);
+      HADAMARD4 (tmp[i][0], tmp[i][1], tmp[i][2], tmp[i][3], a0, a1, a2, a3);
+    }
+  sink (tmp);
+}
+
+/* { dg-final { scan-tree-dump "vectorizing stmts using SLP" "vect" } } */
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */