Enhance vec_pack_trunc for integral mode mask.

For testcase in PR, the patch supports QI:4 -> HI:16 pack with
multi steps(first pack QI:4 -> QI:8 through vec_pack_sbool_trunc_qi,
then pack QI:8 -> HI:16 through vec_pack_trunc_hi).
Similar for QI:2 -> HI:16 which is test4 in mask-pack-prefer-128.c.

gcc/ChangeLog:

	PR target/103771
	* tree-vect-stmts.cc (supportable_narrowing_operation): Enhance
	integral mode mask pack by multi steps which takes
	vec_pack_sbool_trunc_optab as start when elements number is
	less than BITS_PER_UNITS.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/mask-pack-prefer128.c: New test.
	* gcc.target/i386/mask-pack-prefer256.c: New test.
	* gcc.target/i386/pr103771.c: New test.

diff --git a/gcc/testsuite/gcc.target/i386/mask-pack-prefer128.c b/gcc/testsuite/gcc.target/i386/mask-pack-prefer128.c
new file mode 100644 (file)
index 0000000..c9ea37c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/mask-pack-prefer128.c
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-march=skylake-avx512 -O3 -fopenmp-simd -fdump-tree-vect-details -mprefer-vector-width=128" } */
+/* Disabling epilogues until we find a better way to deal with scans.  */
+/* { dg-additional-options "--param vect-epilogues-nomask=0" } */
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 10 "vect" } } */
+/* { dg-final { scan-assembler-not "maskmov" } } */
+
+#include "mask-pack.c"

diff --git a/gcc/testsuite/gcc.target/i386/mask-pack-prefer256.c b/gcc/testsuite/gcc.target/i386/mask-pack-prefer256.c
new file mode 100644 (file)
index 0000000..841f51b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/mask-pack-prefer256.c
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-march=skylake-avx512 -O3 -fopenmp-simd -fdump-tree-vect-details -mprefer-vector-width=256" } */
+/* Disabling epilogues until we find a better way to deal with scans.  */
+/* { dg-additional-options "--param vect-epilogues-nomask=0" } */
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 10 "vect" } } */
+/* { dg-final { scan-assembler-not "maskmov" } } */
+
+#include "mask-pack.c"

diff --git a/gcc/testsuite/gcc.target/i386/pr103771.c b/gcc/testsuite/gcc.target/i386/pr103771.c
new file mode 100644 (file)
index 0000000..a1a9952
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr103771.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-march=cascadelake -O3 -fdump-tree-vect-details -mprefer-vector-width=128" } */
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
+
+typedef unsigned char uint8_t;
+
+static uint8_t x264_clip_uint8 (int x)
+{
+  return x & (~255) ? (-x) >> 31 : x;
+}
+
+void
+mc_weight (uint8_t* __restrict dst, uint8_t* __restrict src,
+          int i_width,int i_scale)
+{
+  for(int x = 0; x < i_width; x++)
+    dst[x] = x264_clip_uint8 (src[x] * i_scale);
+}

diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index 95be4f3..824ebb6 100644 (file)
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -12124,6 +12124,7 @@ supportable_narrowing_operation (enum tree_code code,
   tree intermediate_type, prev_type;
   machine_mode intermediate_mode, prev_mode;
   int i;
+  unsigned HOST_WIDE_INT n_elts;
   bool uns;
 
   *multi_step_cvt = 0;
@@ -12133,8 +12134,9 @@ supportable_narrowing_operation (enum tree_code code,
       c1 = VEC_PACK_TRUNC_EXPR;
       if (VECTOR_BOOLEAN_TYPE_P (narrow_vectype)
          && VECTOR_BOOLEAN_TYPE_P (vectype)
-         && TYPE_MODE (narrow_vectype) == TYPE_MODE (vectype)
-         && SCALAR_INT_MODE_P (TYPE_MODE (vectype)))
+         && SCALAR_INT_MODE_P (TYPE_MODE (vectype))
+         && TYPE_VECTOR_SUBPARTS (vectype).is_constant (&n_elts)
+         && n_elts < BITS_PER_UNIT)
        optab1 = vec_pack_sbool_trunc_optab;
       else
        optab1 = optab_for_tree_code (c1, vectype, optab_default);
@@ -12225,8 +12227,9 @@ supportable_narrowing_operation (enum tree_code code,
          = lang_hooks.types.type_for_mode (intermediate_mode, uns);
       if (VECTOR_BOOLEAN_TYPE_P (intermediate_type)
          && VECTOR_BOOLEAN_TYPE_P (prev_type)
-         && intermediate_mode == prev_mode
-         && SCALAR_INT_MODE_P (prev_mode))
+         && SCALAR_INT_MODE_P (prev_mode)
+         && TYPE_VECTOR_SUBPARTS (intermediate_type).is_constant (&n_elts)
+         && n_elts < BITS_PER_UNIT)
        interm_optab = vec_pack_sbool_trunc_optab;
       else
        interm_optab