fold-const.c (force_fit_type): Unsigned values can overflow if they are sizetype.

	* fold-const.c (force_fit_type): Unsigned values can overflow
	if they are sizetype.
	(int_const_binop): Don't use cache if overflows.
	* cp/typeck.c (dubious_conversion_warning): Suppress if
	TYPE_IS_SIZETYPE.

From-SVN: r36970

gcc/ChangeLog

+Fri Oct 20 13:33:16 2000  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
+
+	* fold-const.c (force_fit_type): Unsigned values can overflow
+	if they are sizetype.
+	(int_const_binop): Don't use cache if overflows.
 2000-10-20  Richard Henderson  <rth@cygnus.com>
 
 	* function.c (locate_and_pad_parm): Zero alignment_pad.

gcc/cp/ChangeLog

+Fri Oct 20 13:54:59 2000  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
+
+	* typeck.c (dubious_conversion_warning): Suppress if TYPE_IS_SIZETYPE.
+
 2000-10-20  Jeffrey Oldham  <oldham@codesourcery.com>
 
 	* decl.c (revert_static_member_fn): Fixed typo.

gcc/cp/typeck.c

@@ -6353,7 +6353,16 @@ dubious_conversion_warnings (type, expr, errtype, fndecl, parmnum)
 	    cp_warning ("%s of negative value `%E' to `%T'",
 			errtype, expr, type);
 	}
-      overflow_warning (expr);
+
+      /* Suppress warning for a sizetype since we never used to issue it.
+	 ??? This needs to be looked at more carefully someday.  */
+      if (TREE_CODE (expr) == INTEGER_CST
+	  && TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
+	  && TYPE_IS_SIZETYPE (TREE_TYPE (expr)))
+	TREE_OVERFLOW (expr) = TREE_CONSTANT_OVERFLOW (expr) = 0;
+      else
+	overflow_warning (expr);
+
       if (TREE_CONSTANT (expr))
 	expr = fold (expr);
     }

gcc/fold-const.c

@@ -216,8 +216,11 @@ force_fit_type (t, overflow)
 	TREE_INT_CST_LOW (t) &= ~((unsigned HOST_WIDE_INT) (-1) << prec);
     }
 
-  /* Unsigned types do not suffer sign extension or overflow.  */
-  if (TREE_UNSIGNED (TREE_TYPE (t)))
+  /* Unsigned types do not suffer sign extension or overflow unless they
+     are a sizetype.  */
+  if (TREE_UNSIGNED (TREE_TYPE (t))
+      && ! (TREE_CODE (TREE_TYPE (t)) == INTEGER_TYPE
+	    && TYPE_IS_SIZETYPE (TREE_TYPE (t))))
     return overflow;
 
   /* If the value's sign bit is set, extend the sign.  */
@@ -1604,7 +1607,8 @@ int_const_binop (code, arg1, arg2, notrunc, forsize)
       abort ();
     }
 
-  if (forsize && hi == 0 && low < 10000)
+  if (forsize && hi == 0 && low < 10000
+      && overflow == 0 && ! TREE_OVERFLOW (arg1) && ! TREE_OVERFLOW (arg2))
     return size_int_type_wide (low, TREE_TYPE (arg1));
   else
     {