re PR middle-end/9707 (Unnecessary range test in switches with less than 4 cases)

	PR optimization/9707.
	* stmt.c (emit_case_nodes): Emit equality comparisons instead
	of recursing if both children are single-valued cases with no
	children.

From-SVN: r79954

gcc/ChangeLog

+2004-03-25  Kazu Hirata  <kazu@cs.umass.edu>
+
+	PR optimization/9707.
+	* stmt.c (emit_case_nodes): Emit equality comparisons instead
+	of recursing if both children are single-valued cases with no
+	children.
+
 2004-03-25  Paul Brook  <paul@codesourcery.com>
 
 	* config/arm/arm.c (vfp_print_multi): Remove.

gcc/stmt.c

@@ -6200,6 +6200,42 @@ emit_case_nodes (rtx index, case_node_ptr node, rtx default_label,
 	      emit_case_nodes (index, node->right, default_label, index_type);
 	    }
 
+	  /* If both children are single-valued cases with no
+	     children, finish up all the work.  This way, we can save
+	     one ordered comparison.  */
+	  else if (tree_int_cst_equal (node->right->low, node->right->high)
+		   && node->right->left == 0
+		   && node->right->right == 0
+		   && tree_int_cst_equal (node->left->low, node->left->high)
+		   && node->left->left == 0
+		   && node->left->right == 0)
+	    {
+	      /* Neither node is bounded.  First distinguish the two sides;
+		 then emit the code for one side at a time.  */
+
+	      /* See if the value matches what the right hand side
+		 wants.  */
+	      do_jump_if_equal (index,
+				convert_modes (mode, imode,
+					       expand_expr (node->right->low,
+							    NULL_RTX,
+							    VOIDmode, 0),
+					       unsignedp),
+				label_rtx (node->right->code_label),
+				unsignedp);
+
+	      /* See if the value matches what the left hand side
+		 wants.  */
+	      do_jump_if_equal (index,
+				convert_modes (mode, imode,
+					       expand_expr (node->left->low,
+							    NULL_RTX,
+							    VOIDmode, 0),
+					       unsignedp),
+				label_rtx (node->left->code_label),
+				unsignedp);
+	    }
+
 	  else
 	    {
 	      /* Neither node is bounded.  First distinguish the two sides;