[PATCH] [vect] Add vect_recog_cond_expr_convert_pattern.

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

>But in principle @2 or @3 could safely differ in sign, you'd then need to ensure
>to insert sign conversions to @2/@3 to the signedness of @4/@5.
Changed.
>you are not testing for this anywhere?
It's tested in vect_recog_cond_expr_convert_pattern, I've move it to match.pd

>Btw, matching up the comments with the types is somewhat difficult,
>maybe using TYPE_AB, TYPE_CD, TYPE_E instead of 1,2,3 will
>make that easier ;)
Changed.
>I think the precision check should be part of the match.pd pattern.  You
>do not check that the comparison operands are integral - I think float
>comparisons would be OK in principle but the precision check will not
>work there.
Restricted to integeral type.

Here's updated patch.

gcc/ChangeLog:

	PR target/103771
	* match.pd (cond_expr_convert_p): New match.
	* tree-vect-patterns.cc (gimple_cond_expr_convert_p): Declare.
	(vect_recog_cond_expr_convert_pattern): New.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/pr103771-2.c: New test.
	* gcc.target/i386/pr103771-3.c: New test.
---
 gcc/match.pd                               | 14 ++++
 gcc/testsuite/gcc.target/i386/pr103771-2.c |  8 ++
 gcc/testsuite/gcc.target/i386/pr103771-3.c | 21 +++++
 gcc/tree-vect-patterns.cc                  | 96 ++++++++++++++++++++++
 4 files changed, 139 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr103771-2.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr103771-3.c

diff --git a/gcc/match.pd b/gcc/match.pd
index 7bbb80172fc..7386ee518a1 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -7683,3 +7683,17 @@ and,
    to the number of trailing zeroes.  */
 (match (ctz_table_index @1 @2 @3)
   (rshift (mult (bit_and:c (negate @1) @1) INTEGER_CST@2) INTEGER_CST@3))
+
+(match (cond_expr_convert_p @0 @2 @3 @6)
+ (cond (simple_comparison@6 @0 @1) (convert@4 @2) (convert@5 @3))
+  (if (INTEGRAL_TYPE_P (type)
+       && INTEGRAL_TYPE_P (TREE_TYPE (@2))
+       && INTEGRAL_TYPE_P (TREE_TYPE (@0))
+       && INTEGRAL_TYPE_P (TREE_TYPE (@3))
+       && TYPE_PRECISION (type) != TYPE_PRECISION (TREE_TYPE (@0))
+       && TYPE_PRECISION (TREE_TYPE (@0))
+	  == TYPE_PRECISION (TREE_TYPE (@2))
+       && TYPE_PRECISION (TREE_TYPE (@0))
+	  == TYPE_PRECISION (TREE_TYPE (@3))
+       && single_use (@4)
+       && single_use (@5))))
diff --git a/gcc/testsuite/gcc.target/i386/pr103771-2.c b/gcc/testsuite/gcc.target/i386/pr103771-2.c
new file mode 100644
index 00000000000..962a3a74ecf
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr103771-2.c
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-march=cascadelake -O3" } */
+/* { dg-final { scan-assembler-not "kunpck" } } */
+/* { dg-final { scan-assembler-not "kand" } } */
+/* { dg-final { scan-assembler-not "kor" } } */
+/* { dg-final { scan-assembler-not "kshift" } } */
+
+#include "pr103771.c"
diff --git a/gcc/testsuite/gcc.target/i386/pr103771-3.c b/gcc/testsuite/gcc.target/i386/pr103771-3.c
new file mode 100644
index 00000000000..ef379b23b12
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr103771-3.c
@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-march=cascadelake -O3" } */
+/* { dg-final { scan-assembler-not "kunpck" } } */
+/* { dg-final { scan-assembler-not "kand" } } */
+/* { dg-final { scan-assembler-not "kor" } } */
+/* { dg-final { scan-assembler-not "kshift" } } */
+
+typedef unsigned char uint8_t;
+
+static uint8_t x264_clip_uint8 (int x, unsigned int y)
+{
+  return x & (~255) ? (-x) >> 31 : y;
+}
+
+void
+mc_weight (uint8_t* __restrict dst, uint8_t* __restrict src,
+	   int i_width,int i_scale, unsigned int* __restrict y)
+{
+  for(int x = 0; x < i_width; x++)
+    dst[x] = x264_clip_uint8 (src[x] * i_scale, y[x]);
+}
diff --git a/gcc/tree-vect-patterns.cc b/gcc/tree-vect-patterns.cc
index 2baf974627e..aa54bc8bf8b 100644
--- a/gcc/tree-vect-patterns.cc
+++ b/gcc/tree-vect-patterns.cc
@@ -924,6 +924,101 @@ vect_reassociating_reduction_p (vec_info *vinfo,
   return true;
 }
 
+/* match.pd function to match
+   (cond (cmp@3 a b) (convert@1 c) (convert@2 d))
+   with conditions:
+   1) @1, @2, c, d, a, b are all integral type.
+   2) There's single_use for both @1 and @2.
+   3) a, c and d have same precision.
+   4) c and @1 have different precision.
+
+   record a and c and d and @3.  */
+
+extern bool gimple_cond_expr_convert_p (tree, tree*, tree (*)(tree));
+
+/* Function vect_recog_cond_expr_convert
+
+   Try to find the following pattern:
+
+   TYPE_AB A,B;
+   TYPE_CD C,D;
+   TYPE_E E;
+   TYPE_E op_true = (TYPE_E) A;
+   TYPE_E op_false = (TYPE_E) B;
+
+   E = C cmp D ? op_true : op_false;
+
+   where
+   TYPE_PRECISION (TYPE_E) != TYPE_PRECISION (TYPE_CD);
+   TYPE_PRECISION (TYPE_AB) == TYPE_PRECISION (TYPE_CD);
+   single_use of op_true and op_false.
+   TYPE_AB could differ in sign.
+
+   Input:
+
+   * STMT_VINFO: The stmt from which the pattern search begins.
+   here it starts with E = c cmp D ? op_true : op_false;
+
+   Output:
+
+   TYPE1 E' = C cmp D ? A : B;
+   TYPE3 E = (TYPE3) E';
+
+   There may extra nop_convert for A or B to handle different signness.
+
+   * TYPE_OUT: The vector type of the output of this pattern.
+
+   * Return value: A new stmt that will be used to replace the sequence of
+   stmts that constitute the pattern. In this case it will be:
+   E = (TYPE3)E';
+   E' = C cmp D ? A : B; is recorded in pattern definition statements;  */
+
+static gimple *
+vect_recog_cond_expr_convert_pattern (vec_info *vinfo,
+				      stmt_vec_info stmt_vinfo, tree *type_out)
+{
+  gassign *last_stmt = dyn_cast <gassign *> (stmt_vinfo->stmt);
+  tree lhs, match[4], temp, type, new_lhs, op2;
+  gimple *cond_stmt;
+  gimple *pattern_stmt;
+
+  if (!last_stmt)
+    return NULL;
+
+  lhs = gimple_assign_lhs (last_stmt);
+
+  /* Find E = C cmp D ? (TYPE3) A ? (TYPE3) B;
+     TYPE_PRECISION (A) == TYPE_PRECISION (C).  */
+  if (!gimple_cond_expr_convert_p (lhs, &match[0], NULL))
+    return NULL;
+
+  vect_pattern_detected ("vect_recog_cond_expr_convert_pattern", last_stmt);
+
+  op2 = match[2];
+  type = TREE_TYPE (match[1]);
+  if (TYPE_SIGN (type) != TYPE_SIGN (TREE_TYPE (match[2])))
+    {
+      op2 = vect_recog_temp_ssa_var (type, NULL);
+      gimple* nop_stmt = gimple_build_assign (op2, CONVERT_EXPR, match[2]);
+      append_pattern_def_seq (vinfo, stmt_vinfo, nop_stmt,
+			      get_vectype_for_scalar_type (vinfo, type));
+    }
+
+  temp = vect_recog_temp_ssa_var (type, NULL);
+  cond_stmt = gimple_build_assign (temp, build3 (COND_EXPR, type, match[3],
+						 match[1], op2));
+  append_pattern_def_seq (vinfo, stmt_vinfo, cond_stmt,
+			  get_vectype_for_scalar_type (vinfo, type));
+  new_lhs = vect_recog_temp_ssa_var (TREE_TYPE (lhs), NULL);
+  pattern_stmt = gimple_build_assign (new_lhs, CONVERT_EXPR, temp);
+  *type_out = STMT_VINFO_VECTYPE (stmt_vinfo);
+
+  if (dump_enabled_p ())
+    dump_printf_loc (MSG_NOTE, vect_location,
+		     "created pattern stmt: %G", pattern_stmt);
+  return pattern_stmt;
+}
+
 /* Function vect_recog_dot_prod_pattern
 
    Try to find the following pattern:
@@ -5492,6 +5587,7 @@ static vect_recog_func vect_vect_recog_func_ptrs[] = {
   /* Must come after over_widening, which narrows the shift as much as
      possible beforehand.  */
   { vect_recog_average_pattern, "average" },
+  { vect_recog_cond_expr_convert_pattern, "cond_expr_convert" },
   { vect_recog_mulhs_pattern, "mult_high" },
   { vect_recog_cast_forwprop_pattern, "cast_forwprop" },
   { vect_recog_widen_mult_pattern, "widen_mult" },
-- 
2.18.1