[2/3] [vect] Add widening add, subtract patterns

Add widening add, subtract patterns to tree-vect-patterns. Update the
widened code of patterns that detect PLUS_EXPR to also detect
WIDEN_PLUS_EXPR. These patterns take 2 vectors with N elements of size
S and perform an add/subtract on the elements, storing the results as N
elements of size 2*S (in 2 result vectors). This is implemented in the
aarch64 backend as addl,addl2 and subl,subl2 respectively. Add aarch64
tests for patterns.

gcc/ChangeLog:
	* doc/generic.texi: Document new widen_plus/minus_lo/hi tree codes.
	* doc/md.texi: Document new widenening add/subtract hi/lo optabs.
	* expr.c (expand_expr_real_2): Add widen_add, widen_subtract cases.
	* optabs-tree.c (optab_for_tree_code): Add case for widening optabs.
	* optabs.def (OPTAB_D): Define vectorized widen add, subtracts.
	* tree-cfg.c (verify_gimple_assign_binary): Add case for widening adds,
	subtracts.
	* tree-inline.c (estimate_operator_cost): Add case for widening adds,
	subtracts.
	* tree-vect-generic.c (expand_vector_operations_1): Add case for
	widening adds, subtracts
	* tree-vect-patterns.c (vect_recog_widen_add_pattern): New recog
	pattern.
	(vect_recog_widen_sub_pattern): New recog pattern.
	(vect_recog_average_pattern): Update widened add code.
	(vect_recog_average_pattern): Update widened add code.
	* tree-vect-stmts.c (vectorizable_conversion): Add case for widened add,
	subtract.
	(supportable_widening_operation): Add case for widened add, subtract.
	* tree.def
	(WIDEN_PLUS_EXPR): New tree code.
	(WIDEN_MINUS_EXPR): New tree code.
	(VEC_WIDEN_ADD_HI_EXPR): New tree code.
	(VEC_WIDEN_PLUS_LO_EXPR): New tree code.
	(VEC_WIDEN_MINUS_HI_EXPR): New tree code.
	(VEC_WIDEN_MINUS_LO_EXPR): New tree code.

gcc/testsuite/ChangeLog:

	* gcc.target/aarch64/vect-widen-add.c: New test.
	* gcc.target/aarch64/vect-widen-sub.c: New test.

1 files changed, 28 insertions, 3 deletions

diff --git a/gcc/tree-vect-patterns.c b/gcc/tree-vect-patterns.c
index f68a87e..f2ce75a 100644
--- a/gcc/tree-vect-patterns.c
+++ b/gcc/tree-vect-patterns.c
@@ -1148,7 +1148,7 @@ vect_recog_sad_pattern (vec_info *vinfo,
   /* FORNOW.  Can continue analyzing the def-use chain when this stmt in a phi
      inside the loop (in case we are analyzing an outer-loop).  */
   vect_unpromoted_value unprom[2];
-  if (!vect_widened_op_tree (vinfo, diff_stmt_vinfo, MINUS_EXPR, MINUS_EXPR,
+  if (!vect_widened_op_tree (vinfo, diff_stmt_vinfo, MINUS_EXPR, WIDEN_MINUS_EXPR,
 			     false, 2, unprom, &half_type))
     return NULL;
 
@@ -1262,6 +1262,29 @@ vect_recog_widen_mult_pattern (vec_info *vinfo, stmt_vec_info last_stmt_info,
 				      "vect_recog_widen_mult_pattern");
 }
 
+/* Try to detect addition on widened inputs, converting PLUS_EXPR
+   to WIDEN_PLUS_EXPR.  See vect_recog_widen_op_pattern for details.  */
+
+static gimple *
+vect_recog_widen_plus_pattern (vec_info *vinfo, stmt_vec_info last_stmt_info,
+			       tree *type_out)
+{
+  return vect_recog_widen_op_pattern (vinfo, last_stmt_info, type_out,
+				      PLUS_EXPR, WIDEN_PLUS_EXPR, false,
+				      "vect_recog_widen_plus_pattern");
+}
+
+/* Try to detect subtraction on widened inputs, converting MINUS_EXPR
+   to WIDEN_MINUS_EXPR.  See vect_recog_widen_op_pattern for details.  */
+static gimple *
+vect_recog_widen_minus_pattern (vec_info *vinfo, stmt_vec_info last_stmt_info,
+			       tree *type_out)
+{
+  return vect_recog_widen_op_pattern (vinfo, last_stmt_info, type_out,
+				      MINUS_EXPR, WIDEN_MINUS_EXPR, false,
+				      "vect_recog_widen_minus_pattern");
+}
+
 /* Function vect_recog_pow_pattern
 
    Try to find the following pattern:
@@ -1978,7 +2001,7 @@ vect_recog_average_pattern (vec_info *vinfo,
   vect_unpromoted_value unprom[3];
   tree new_type;
   unsigned int nops = vect_widened_op_tree (vinfo, plus_stmt_info, PLUS_EXPR,
-					    PLUS_EXPR, false, 3,
+					    WIDEN_PLUS_EXPR, false, 3,
 					    unprom, &new_type);
   if (nops == 0)
     return NULL;
@@ -5249,7 +5272,9 @@ static vect_recog_func vect_vect_recog_func_ptrs[] = {
      of mask conversion that are needed for gather and scatter
      internal functions.  */
   { vect_recog_gather_scatter_pattern, "gather_scatter" },
-  { vect_recog_mask_conversion_pattern, "mask_conversion" }
+  { vect_recog_mask_conversion_pattern, "mask_conversion" },
+  { vect_recog_widen_plus_pattern, "widen_plus" },
+  { vect_recog_widen_minus_pattern, "widen_minus" },
 };
 
 const unsigned int NUM_PATTERNS = ARRAY_SIZE (vect_vect_recog_func_ptrs);