fold-const.c (make_range): Cleanup type checking through function.

2004-06-23  Eric Christopher  <echristo@redhat.com>

	* fold-const.c (make_range): Cleanup type checking through function.
	Remove orig_type. Replace with checks to exp_type and arg0_type.
	Clarify comment when converting from unsigned to signed.

From-SVN: r83576

gcc/ChangeLog

 2004-06-23  Eric Christopher  <echristo@redhat.com>
 
+	* fold-const.c (make_range): Cleanup type checking through function.
+	Remove orig_type. Replace with checks to exp_type and arg0_type.
+	Clarify comment when converting from unsigned to signed.
+
+2004-06-23  Eric Christopher  <echristo@redhat.com>
+
 	* config/mips/mips.c (mips_use_dfa_pipeline_interface): Add R3000.
 	* config/mips/mips.md: Remove R3000 scheduling description.
 	* config/mips/3000.md: New file.

gcc/fold-const.c

@@ -3532,8 +3532,8 @@ static tree
 make_range (tree exp, int *pin_p, tree *plow, tree *phigh)
 {
   enum tree_code code;
-  tree arg0 = NULL_TREE, arg1 = NULL_TREE, type = NULL_TREE;
-  tree orig_type = NULL_TREE;
+  tree arg0 = NULL_TREE, arg1 = NULL_TREE;
+  tree exp_type = NULL_TREE, arg0_type = NULL_TREE;
   int in_p, n_in_p;
   tree low, high, n_low, n_high;
 
@@ -3549,6 +3549,7 @@ make_range (tree exp, int *pin_p, tree *plow, tree *phigh)
   while (1)
     {
       code = TREE_CODE (exp);
+      exp_type = TREE_TYPE (exp);
 
       if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (code)))
 	{
@@ -3557,7 +3558,7 @@ make_range (tree exp, int *pin_p, tree *plow, tree *phigh)
 	  if (TREE_CODE_CLASS (code) == '<'
 	      || TREE_CODE_CLASS (code) == '1'
 	      || TREE_CODE_CLASS (code) == '2')
-	    type = TREE_TYPE (arg0);
+	    arg0_type = TREE_TYPE (arg0);
 	  if (TREE_CODE_CLASS (code) == '2'
 	      || TREE_CODE_CLASS (code) == '<'
 	      || (TREE_CODE_CLASS (code) == 'e'
@@ -3565,11 +3566,6 @@ make_range (tree exp, int *pin_p, tree *plow, tree *phigh)
 	    arg1 = TREE_OPERAND (exp, 1);
 	}
 
-      /* Set ORIG_TYPE as soon as TYPE is non-null so that we do not
-	 lose a cast by accident.  */
-      if (type != NULL_TREE && orig_type == NULL_TREE)
-	orig_type = type;
-
       switch (code)
 	{
 	case TRUTH_NOT_EXPR:
@@ -3612,16 +3608,15 @@ make_range (tree exp, int *pin_p, tree *plow, tree *phigh)
 	      abort ();
 	    }
 
-	  exp = arg0;
-
 	  /* If this is an unsigned comparison, we also know that EXP is
 	     greater than or equal to zero.  We base the range tests we make
 	     on that fact, so we record it here so we can parse existing
-	     range tests.  */
-	  if (TYPE_UNSIGNED (type) && (low == 0 || high == 0))
+	     range tests.  We test arg0_type since often the return type
+	     of, e.g. EQ_EXPR, is boolean.  */
+	  if (TYPE_UNSIGNED (arg0_type) && (low == 0 || high == 0))
 	    {
 	      if (! merge_ranges (&n_in_p, &n_low, &n_high, in_p, low, high,
-				  1, fold_convert (type, integer_zero_node),
+				  1, fold_convert (arg0_type, integer_zero_node),
 				  NULL_TREE))
 		break;
 
@@ -3635,18 +3630,20 @@ make_range (tree exp, int *pin_p, tree *plow, tree *phigh)
 		  in_p = ! in_p;
 		  high = range_binop (MINUS_EXPR, NULL_TREE, low, 0,
 				      integer_one_node, 0);
-		  low = fold_convert (type, integer_zero_node);
+		  low = fold_convert (arg0_type, integer_zero_node);
 		}
 	    }
+
+	  exp = arg0;
 	  continue;
 
 	case NEGATE_EXPR:
 	  /* (-x) IN [a,b] -> x in [-b, -a]  */
-	  n_low = range_binop (MINUS_EXPR, type,
-			       fold_convert (type, integer_zero_node),
+	  n_low = range_binop (MINUS_EXPR, exp_type,
+			       fold_convert (exp_type, integer_zero_node),
 			       0, high, 1);
-	  n_high = range_binop (MINUS_EXPR, type,
-				fold_convert (type, integer_zero_node),
+	  n_high = range_binop (MINUS_EXPR, exp_type,
+				fold_convert (exp_type, integer_zero_node),
 				0, low, 0);
 	  low = n_low, high = n_high;
 	  exp = arg0;
@@ -3654,8 +3651,8 @@ make_range (tree exp, int *pin_p, tree *plow, tree *phigh)
 
 	case BIT_NOT_EXPR:
 	  /* ~ X -> -X - 1  */
-	  exp = build2 (MINUS_EXPR, type, negate_expr (arg0),
-			fold_convert (type, integer_one_node));
+	  exp = build2 (MINUS_EXPR, exp_type, negate_expr (arg0),
+			fold_convert (exp_type, integer_one_node));
 	  continue;
 
 	case PLUS_EXPR:  case MINUS_EXPR:
@@ -3667,9 +3664,9 @@ make_range (tree exp, int *pin_p, tree *plow, tree *phigh)
 	     the bounds don't overflow.  For unsigned, overflow is defined
 	     and this is exactly the right thing.  */
 	  n_low = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
-			       type, low, 0, arg1, 0);
+			       arg0_type, low, 0, arg1, 0);
 	  n_high = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
-				type, high, 1, arg1, 0);
+				arg0_type, high, 1, arg1, 0);
 	  if ((n_low != 0 && TREE_OVERFLOW (n_low))
 	      || (n_high != 0 && TREE_OVERFLOW (n_high)))
 	    break;
@@ -3678,9 +3675,9 @@ make_range (tree exp, int *pin_p, tree *plow, tree *phigh)
 	     value thus making n_high < n_low, and normalize it.  */
 	  if (n_low && n_high && tree_int_cst_lt (n_high, n_low))
 	    {
-	      low = range_binop (PLUS_EXPR, type, n_high, 0,
+	      low = range_binop (PLUS_EXPR, arg0_type, n_high, 0,
 				 integer_one_node, 0);
-	      high = range_binop (MINUS_EXPR, type, n_low, 0,
+	      high = range_binop (MINUS_EXPR, arg0_type, n_low, 0,
 				  integer_one_node, 0);
 
 	      /* If the range is of the form +/- [ x+1, x ], we won't
@@ -3700,46 +3697,50 @@ make_range (tree exp, int *pin_p, tree *plow, tree *phigh)
 	  continue;
 
 	case NOP_EXPR:  case NON_LVALUE_EXPR:  case CONVERT_EXPR:
-	  if (TYPE_PRECISION (type) > TYPE_PRECISION (orig_type))
+	  if (TYPE_PRECISION (arg0_type) > TYPE_PRECISION (exp_type))
 	    break;
 
-	  if (! INTEGRAL_TYPE_P (type)
-	      || (low != 0 && ! int_fits_type_p (low, type))
-	      || (high != 0 && ! int_fits_type_p (high, type)))
+	  if (! INTEGRAL_TYPE_P (arg0_type)
+	      || (low != 0 && ! int_fits_type_p (low, arg0_type))
+	      || (high != 0 && ! int_fits_type_p (high, arg0_type)))
 	    break;
 
 	  n_low = low, n_high = high;
 
 	  if (n_low != 0)
-	    n_low = fold_convert (type, n_low);
+	    n_low = fold_convert (arg0_type, n_low);
 
 	  if (n_high != 0)
-	    n_high = fold_convert (type, n_high);
+	    n_high = fold_convert (arg0_type, n_high);
+
+
+	  /* If we're converting arg0 from an unsigned type, to exp,
+	     a signed type,  we will be doing the compairson as unsigned.
+	     The tests above have already verified that LOW and HIGH
+	     are both positive.
 
-	  /* If we're converting from an unsigned to a signed type,
-	     we will be doing the comparison as unsigned.  The tests above
-	     have already verified that LOW and HIGH are both positive.
+	     So we have to ensure that we will handle large unsigned
+	     values the same way that the current signed bounds treat
+	     negative values.  */
 
-	     So we have to make sure that the original unsigned value will
-	     be interpreted as positive.  */
-	  if (TYPE_UNSIGNED (type) && ! TYPE_UNSIGNED (TREE_TYPE (exp)))
+	  if (!TYPE_UNSIGNED (exp_type) && TYPE_UNSIGNED (arg0_type))
 	    {
-	      tree equiv_type = lang_hooks.types.type_for_mode
-		(TYPE_MODE (type), 1);
 	      tree high_positive;
+	      tree equiv_type = lang_hooks.types.type_for_mode
+		(TYPE_MODE (arg0_type), 1);
 
 	      /* A range without an upper bound is, naturally, unbounded.
 		 Since convert would have cropped a very large value, use
 		 the max value for the destination type.  */
 	      high_positive
 		= TYPE_MAX_VALUE (equiv_type) ? TYPE_MAX_VALUE (equiv_type)
-		  : TYPE_MAX_VALUE (type);
+		: TYPE_MAX_VALUE (arg0_type);
 
-	      if (TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (exp)))
-	        high_positive = fold (build2 (RSHIFT_EXPR, type,
-					      fold_convert (type,
+	      if (TYPE_PRECISION (exp_type) == TYPE_PRECISION (arg0_type))
+		high_positive = fold (build2 (RSHIFT_EXPR, arg0_type,
+					      fold_convert (arg0_type,
 							    high_positive),
-					      fold_convert (type,
+					      fold_convert (arg0_type,
 							    integer_one_node)));
 
 	      /* If the low bound is specified, "and" the range with the
@@ -3749,7 +3750,7 @@ make_range (tree exp, int *pin_p, tree *plow, tree *phigh)
 		{
 		  if (! merge_ranges (&n_in_p, &n_low, &n_high,
 				      1, n_low, n_high, 1,
-				      fold_convert (type, integer_zero_node),
+				      fold_convert (arg0_type, integer_zero_node),
 				      high_positive))
 		    break;
 
@@ -3761,7 +3762,7 @@ make_range (tree exp, int *pin_p, tree *plow, tree *phigh)
 		     that will be interpreted as negative.  */
 		  if (! merge_ranges (&n_in_p, &n_low, &n_high,
 				      0, n_low, n_high, 1,
-				      fold_convert (type, integer_zero_node),
+				      fold_convert (arg0_type, integer_zero_node),
 				      high_positive))
 		    break;