call.c (build_over_call): Convert builtin abs, labs and fabs to tree-codes.

	* call.c (build_over_call): Convert builtin abs, labs and fabs to
	tree-codes.
	* decl.c (init_decl_processing): Reenable abs, labs and fabs as
	builtins.

From-SVN: r17900

gcc/cp/ChangeLog

+Fri Feb 13 02:26:10 1998  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>
+
+	* call.c (build_over_call): Convert builtin abs, labs and fabs to
+	tree-codes.
+	* decl.c (init_decl_processing): Reenable abs, labs and fabs as
+	builtins.
+
 Fri Feb 13 01:36:42 1998  Jason Merrill  <jason@yorick.cygnus.com>
 
 	* call.c (standard_conversion): A BASE_CONV replaces an RVALUE_CONV.

gcc/cp/call.c

@@ -5656,6 +5656,23 @@ build_over_call (fn, convs, args, flags)
   else
     fn = build_addr_func (fn);
 
+  /* Recognize certain built-in functions so we can make tree-codes
+     other than CALL_EXPR.  We do this when it enables fold-const.c
+     to do something useful.  */
+
+  if (TREE_CODE (fn) == ADDR_EXPR
+      && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL
+      && DECL_BUILT_IN (TREE_OPERAND (fn, 0)))
+    switch (DECL_FUNCTION_CODE (TREE_OPERAND (fn, 0)))
+      {
+      case BUILT_IN_ABS:
+      case BUILT_IN_LABS:
+      case BUILT_IN_FABS:
+	if (converted_args == 0)
+	  return integer_zero_node;
+	return build_unary_op (ABS_EXPR, TREE_VALUE (converted_args), 0);
+      }
+
   fn = build_call (fn, TREE_TYPE (TREE_TYPE (TREE_TYPE (fn))), converted_args);
   if (TREE_TYPE (fn) == void_type_node)
     return fn;

gcc/cp/decl.c

@@ -5333,11 +5333,9 @@ init_decl_processing ()
 
   if (!flag_no_builtin)
     {
-#if 0 /* These do not work well with libg++.  */
       builtin_function ("abs", int_ftype_int, BUILT_IN_ABS, NULL_PTR);
       builtin_function ("fabs", double_ftype_double, BUILT_IN_FABS, NULL_PTR);
       builtin_function ("labs", long_ftype_long, BUILT_IN_LABS, NULL_PTR);
-#endif
       builtin_function ("fabsf", float_ftype_float, BUILT_IN_FABS, NULL_PTR);
       builtin_function ("fabsl", ldouble_ftype_ldouble, BUILT_IN_FABS,
 			NULL_PTR);