re PR tree-optimization/15784 (fold misses binary optimization)

        PR tree-optimization/15784
        * fold-const.c (fold): Fold ~A + 1 to -A.  Fold -A - 1
        and -1 - A to ~A.


        * stmt.c (expand_case): Don't change index_type.  Convert minval
        to the proper type.

From-SVN: r96289

gcc/ChangeLog

 2005-03-11  James A. Morrison  <phython@gcc.gnu.org>
 
+        PR tree-optimization/15784
+        * fold-const.c (fold): Fold ~A + 1 to -A.  Fold -A - 1
+        and -1 - A to ~A.
+
+        * stmt.c (expand_case): Don't change index_type.  Convert minval
+        to the proper type.
+
 	PR tree-optimization/20130
 	* fold-const.c (fold): Fold x * -1 into -x.
 
@@ -722,7 +729,7 @@
 	Revert for now:
 	2005-03-03  James A. Morrison  <phython@gcc.gnu.org>
 	PR tree-optimization/15784
-	* fold-const.c (fold): Fold ~A + 1 to -1.  Fold -A - 1
+	* fold-const.c (fold): Fold ~A + 1 to -A.  Fold -A - 1
 	and -1 - A to ~A.
 
 2005-03-04  Ben Elliston  <bje@au.ibm.com>
@@ -756,7 +763,7 @@
 2005-03-03  James A. Morrison  <phython@gcc.gnu.org>
 
 	PR tree-optimization/15784
-	* fold-const.c (fold): Fold ~A + 1 to -1.  Fold -A - 1
+	* fold-const.c (fold): Fold ~A + 1 to -A.  Fold -A - 1
 	and -1 - A to ~A.
 
 2005-03-03  David Edelsohn  <edelsohn@gnu.org>

gcc/fold-const.c

@@ -7198,6 +7198,11 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
       if (TREE_CODE (arg0) == NEGATE_EXPR
 	  && reorder_operands_p (TREE_OPERAND (arg0, 0), arg1))
 	return fold (build2 (MINUS_EXPR, type, arg1, TREE_OPERAND (arg0, 0)));
+      /* Convert ~A + 1 to -A.  */
+      if (INTEGRAL_TYPE_P (type)
+	  && TREE_CODE (arg0) == BIT_NOT_EXPR
+	  && integer_onep (arg1))
+	return fold (build1 (NEGATE_EXPR, type, TREE_OPERAND (arg0, 0)));
 
       if (TREE_CODE (type) == COMPLEX_TYPE)
 	{
@@ -7636,6 +7641,16 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
 	  && reorder_operands_p (arg0, arg1))
 	return fold (build2 (MINUS_EXPR, type, negate_expr (arg1),
 			     TREE_OPERAND (arg0, 0)));
+      /* Convert -A - 1 to ~A.  */
+      if (INTEGRAL_TYPE_P (type)
+	  && TREE_CODE (arg0) == NEGATE_EXPR
+	  && integer_onep (arg1))
+	return fold (build1 (BIT_NOT_EXPR, type, TREE_OPERAND (arg0, 0)));
+
+      /* Convert -1 - A to ~A.  */
+      if (INTEGRAL_TYPE_P (type)
+	  && integer_all_onesp (arg0))
+	return fold (build1 (BIT_NOT_EXPR, type, arg1));
 
       if (TREE_CODE (type) == COMPLEX_TYPE)
 	{

gcc/stmt.c

@@ -2424,7 +2424,7 @@ expand_case (tree exp)
 	  if (compare_tree_int (minval, 0) > 0
 	      && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0)
 	    {
-	      minval = integer_zero_node;
+	      minval = fold_convert (index_type, integer_zero_node);
 	      range = maxval;
 	    }
 	  emit_case_bit_tests (index_type, index_expr, minval, range,
@@ -2502,7 +2502,6 @@ expand_case (tree exp)
 			    table_label, default_label))
 	    {
 	      bool ok;
-	      index_type = integer_type_node;
 
 	      /* Index jumptables from zero for suitable values of
                  minval to avoid a subtraction.  */
@@ -2510,7 +2509,7 @@ expand_case (tree exp)
 		  && compare_tree_int (minval, 0) > 0
 		  && compare_tree_int (minval, 3) < 0)
 		{
-		  minval = integer_zero_node;
+		  minval = fold_convert (index_type, integer_zero_node);
 		  range = maxval;
 		}