[PATCH v3] Vect: Support truncate after .SAT_SUB pattern in zip

[pan2.li@intel.com]

From: Pan Li <pan2.li@intel.com>

The zip benchmark of coremark-pro have one SAT_SUB like pattern but
truncated as below:

void test (uint16_t *x, unsigned b, unsigned n)
{
  unsigned a = 0;
  register uint16_t *p = x;

  do {
    a = *--p;
    *p = (uint16_t)(a >= b ? a - b : 0); // Truncate after .SAT_SUB
  } while (--n);
}

It will have gimple before vect pass,  it cannot hit any pattern of
SAT_SUB and then cannot vectorize to SAT_SUB.

_2 = a_11 - b_12(D);
iftmp.0_13 = (short unsigned int) _2;
_18 = a_11 >= b_12(D);
iftmp.0_5 = _18 ? iftmp.0_13 : 0;

This patch would like to improve the pattern match to recog above
as truncate after .SAT_SUB pattern.  Then we will have the pattern
similar to below,  as well as eliminate the first 3 dead stmt.

_2 = a_11 - b_12(D);
iftmp.0_13 = (short unsigned int) _2;
_18 = a_11 >= b_12(D);
iftmp.0_5 = (short unsigned int).SAT_SUB (a_11, b_12(D));

The below tests are passed for this patch.
1. The rv64gcv fully regression tests.
2. The rv64gcv build with glibc.
3. The x86 bootstrap tests.
4. The x86 fully regression tests.

gcc/ChangeLog:

	* match.pd: Add convert description for minus and capture.
	* tree-vect-patterns.cc (vect_recog_build_binary_gimple_call): Add
	new logic to handle in_type is incompatibile with out_type,  as
	well as rename from.
	(vect_recog_build_binary_gimple_stmt): Rename to.
	(vect_recog_sat_add_pattern): Leverage above renamed func.
	(vect_recog_sat_sub_pattern): Ditto.

Signed-off-by: Pan Li <pan2.li@intel.com>
---
 gcc/match.pd              |  4 +--
 gcc/tree-vect-patterns.cc | 51 ++++++++++++++++++++++++---------------
 2 files changed, 33 insertions(+), 22 deletions(-)

diff --git a/gcc/match.pd b/gcc/match.pd
index cf8a399a744..820591a36b3 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3164,9 +3164,9 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 /* Unsigned saturation sub, case 2 (branch with ge):
    SAT_U_SUB = X >= Y ? X - Y : 0.  */
 (match (unsigned_integer_sat_sub @0 @1)
- (cond^ (ge @0 @1) (minus @0 @1) integer_zerop)
+ (cond^ (ge @0 @1) (convert? (minus (convert1? @0) (convert1? @1))) integer_zerop)
  (if (INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type)
-      && types_match (type, @0, @1))))
+      && TYPE_UNSIGNED (TREE_TYPE (@0)) && types_match (@0, @1))))
 
 /* Unsigned saturation sub, case 3 (branchless with gt):
    SAT_U_SUB = (X - Y) * (X > Y).  */
diff --git a/gcc/tree-vect-patterns.cc b/gcc/tree-vect-patterns.cc
index cef901808eb..519d15f2a43 100644
--- a/gcc/tree-vect-patterns.cc
+++ b/gcc/tree-vect-patterns.cc
@@ -4490,26 +4490,37 @@ vect_recog_mult_pattern (vec_info *vinfo,
 extern bool gimple_unsigned_integer_sat_add (tree, tree*, tree (*)(tree));
 extern bool gimple_unsigned_integer_sat_sub (tree, tree*, tree (*)(tree));
 
-static gcall *
-vect_recog_build_binary_gimple_call (vec_info *vinfo, gimple *stmt,
+static gimple *
+vect_recog_build_binary_gimple_stmt (vec_info *vinfo, stmt_vec_info stmt_info,
 				     internal_fn fn, tree *type_out,
-				     tree op_0, tree op_1)
+				     tree lhs, tree op_0, tree op_1)
 {
   tree itype = TREE_TYPE (op_0);
-  tree vtype = get_vectype_for_scalar_type (vinfo, itype);
+  tree otype = TREE_TYPE (lhs);
+  tree v_itype = get_vectype_for_scalar_type (vinfo, itype);
+  tree v_otype = get_vectype_for_scalar_type (vinfo, otype);
 
-  if (vtype != NULL_TREE
-    && direct_internal_fn_supported_p (fn, vtype, OPTIMIZE_FOR_BOTH))
+  if (v_itype != NULL_TREE && v_otype != NULL_TREE
+    && direct_internal_fn_supported_p (fn, v_itype, OPTIMIZE_FOR_BOTH))
     {
       gcall *call = gimple_build_call_internal (fn, 2, op_0, op_1);
+      tree in_ssa = vect_recog_temp_ssa_var (itype, NULL);
 
-      gimple_call_set_lhs (call, vect_recog_temp_ssa_var (itype, NULL));
+      gimple_call_set_lhs (call, in_ssa);
       gimple_call_set_nothrow (call, /* nothrow_p */ false);
-      gimple_set_location (call, gimple_location (stmt));
+      gimple_set_location (call, gimple_location (STMT_VINFO_STMT (stmt_info)));
+
+      *type_out = v_otype;
 
-      *type_out = vtype;
+      if (types_compatible_p (itype, otype))
+	return call;
+      else
+	{
+	  append_pattern_def_seq (vinfo, stmt_info, call, v_itype);
+	  tree out_ssa = vect_recog_temp_ssa_var (otype, NULL);
 
-      return call;
+	  return gimple_build_assign (out_ssa, NOP_EXPR, in_ssa);
+	}
     }
 
   return NULL;
@@ -4541,13 +4552,13 @@ vect_recog_sat_add_pattern (vec_info *vinfo, stmt_vec_info stmt_vinfo,
 
   if (gimple_unsigned_integer_sat_add (lhs, ops, NULL))
     {
-      gcall *call = vect_recog_build_binary_gimple_call (vinfo, last_stmt,
-							 IFN_SAT_ADD, type_out,
-							 ops[0], ops[1]);
-      if (call)
+      gimple *stmt = vect_recog_build_binary_gimple_stmt (vinfo, stmt_vinfo,
+							  IFN_SAT_ADD, type_out,
+							  lhs, ops[0], ops[1]);
+      if (stmt)
 	{
 	  vect_pattern_detected ("vect_recog_sat_add_pattern", last_stmt);
-	  return call;
+	  return stmt;
 	}
     }
 
@@ -4579,13 +4590,13 @@ vect_recog_sat_sub_pattern (vec_info *vinfo, stmt_vec_info stmt_vinfo,
 
   if (gimple_unsigned_integer_sat_sub (lhs, ops, NULL))
     {
-      gcall *call = vect_recog_build_binary_gimple_call (vinfo, last_stmt,
-							 IFN_SAT_SUB, type_out,
-							 ops[0], ops[1]);
-      if (call)
+      gimple *stmt = vect_recog_build_binary_gimple_stmt (vinfo, stmt_vinfo,
+							  IFN_SAT_SUB, type_out,
+							  lhs, ops[0], ops[1]);
+      if (stmt)
 	{
 	  vect_pattern_detected ("vect_recog_sat_sub_pattern", last_stmt);
-	  return call;
+	  return stmt;
 	}
     }
 
-- 
2.34.1