vect: Use an array to replace 3 relevant variables

It's better to place 3 relevant independent variables into array, since we
have requirement to access them via an index in the following patch. At the
same time, this change may get some duplicated code be more compact.

2024-06-16 Feng Xue <fxue@os.amperecomputing.com>

gcc/
	* tree-vect-loop.cc (vect_transform_reduction): Replace vec_oprnds0/1/2
	with one new array variable vec_oprnds[3].

1 files changed, 18 insertions, 25 deletions

diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 27f77ed..1d60ac4 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -8580,9 +8580,7 @@ vect_transform_reduction (loop_vec_info loop_vinfo,
 
   /* Transform.  */
   tree new_temp = NULL_TREE;
-  auto_vec<tree> vec_oprnds0;
-  auto_vec<tree> vec_oprnds1;
-  auto_vec<tree> vec_oprnds2;
+  auto_vec<tree> vec_oprnds[3];
 
   if (dump_enabled_p ())
     dump_printf_loc (MSG_NOTE, vect_location, "transform reduction.\n");
@@ -8630,14 +8628,15 @@ vect_transform_reduction (loop_vec_info loop_vinfo,
      definition.  */
   if (!cond_fn_p)
     {
+      gcc_assert (reduc_index >= 0 && reduc_index <= 2);
       vect_get_vec_defs (loop_vinfo, stmt_info, slp_node, ncopies,
 			 single_defuse_cycle && reduc_index == 0
-			 ? NULL_TREE : op.ops[0], &vec_oprnds0,
+			 ? NULL_TREE : op.ops[0], &vec_oprnds[0],
 			 single_defuse_cycle && reduc_index == 1
-			 ? NULL_TREE : op.ops[1], &vec_oprnds1,
+			 ? NULL_TREE : op.ops[1], &vec_oprnds[1],
 			 op.num_ops == 3
 			 && !(single_defuse_cycle && reduc_index == 2)
-			 ? op.ops[2] : NULL_TREE, &vec_oprnds2);
+			 ? op.ops[2] : NULL_TREE, &vec_oprnds[2]);
     }
   else
     {
@@ -8645,12 +8644,12 @@ vect_transform_reduction (loop_vec_info loop_vinfo,
 	 vectype.  */
       gcc_assert (single_defuse_cycle
 		  && (reduc_index == 1 || reduc_index == 2));
-      vect_get_vec_defs (loop_vinfo, stmt_info, slp_node, ncopies,
-			 op.ops[0], truth_type_for (vectype_in), &vec_oprnds0,
+      vect_get_vec_defs (loop_vinfo, stmt_info, slp_node, ncopies, op.ops[0],
+			 truth_type_for (vectype_in), &vec_oprnds[0],
 			 reduc_index == 1 ? NULL_TREE : op.ops[1],
-			 NULL_TREE, &vec_oprnds1,
+			 NULL_TREE, &vec_oprnds[1],
 			 reduc_index == 2 ? NULL_TREE : op.ops[2],
-			 NULL_TREE, &vec_oprnds2);
+			 NULL_TREE, &vec_oprnds[2]);
     }
 
   /* For single def-use cycles get one copy of the vectorized reduction
@@ -8658,20 +8657,21 @@ vect_transform_reduction (loop_vec_info loop_vinfo,
   if (single_defuse_cycle)
     {
       vect_get_vec_defs (loop_vinfo, stmt_info, slp_node, 1,
-			 reduc_index == 0 ? op.ops[0] : NULL_TREE, &vec_oprnds0,
-			 reduc_index == 1 ? op.ops[1] : NULL_TREE, &vec_oprnds1,
+			 reduc_index == 0 ? op.ops[0] : NULL_TREE,
+			 &vec_oprnds[0],
+			 reduc_index == 1 ? op.ops[1] : NULL_TREE,
+			 &vec_oprnds[1],
 			 reduc_index == 2 ? op.ops[2] : NULL_TREE,
-			 &vec_oprnds2);
+			 &vec_oprnds[2]);
     }
 
   bool emulated_mixed_dot_prod = vect_is_emulated_mixed_dot_prod (stmt_info);
+  unsigned num = vec_oprnds[reduc_index == 0 ? 1 : 0].length ();
 
-  unsigned num = (reduc_index == 0
-		  ? vec_oprnds1.length () : vec_oprnds0.length ());
   for (unsigned i = 0; i < num; ++i)
     {
       gimple *new_stmt;
-      tree vop[3] = { vec_oprnds0[i], vec_oprnds1[i], NULL_TREE };
+      tree vop[3] = { vec_oprnds[0][i], vec_oprnds[1][i], NULL_TREE };
       if (masked_loop_p && !mask_by_cond_expr)
 	{
 	  /* No conditional ifns have been defined for dot-product yet.  */
@@ -8696,7 +8696,7 @@ vect_transform_reduction (loop_vec_info loop_vinfo,
       else
 	{
 	  if (op.num_ops >= 3)
-	    vop[2] = vec_oprnds2[i];
+	    vop[2] = vec_oprnds[2][i];
 
 	  if (masked_loop_p && mask_by_cond_expr)
 	    {
@@ -8727,14 +8727,7 @@ vect_transform_reduction (loop_vec_info loop_vinfo,
 	}
 
       if (single_defuse_cycle && i < num - 1)
-	{
-	  if (reduc_index == 0)
-	    vec_oprnds0.safe_push (gimple_get_lhs (new_stmt));
-	  else if (reduc_index == 1)
-	    vec_oprnds1.safe_push (gimple_get_lhs (new_stmt));
-	  else if (reduc_index == 2)
-	    vec_oprnds2.safe_push (gimple_get_lhs (new_stmt));
-	}
+	vec_oprnds[reduc_index].safe_push (gimple_get_lhs (new_stmt));
       else if (slp_node)
 	slp_node->push_vec_def (new_stmt);
       else