cp-tree.h, tree.c: New function non_cast_lvalue_p.

2002-09-13  Matt Austern  <austern@apple.com>
        * cp/cp-tree.h, cp/tree.c: New function non_cast_lvalue_p.
        * cp/call.c: Change call-by-const-reference mechanism to use
        non_cast_lvalue_p when deciding whether the create a temporary.
        We need a temporary when passing, e.g. (long) x by const ref.
        * testsuite/g++.dg/other/constref[12].C: New, regression tests for
        passing a cast expression to a function by const reference.

From-SVN: r57115

gcc/ChangeLog

+2002-09-13  Matt Austern  <austern@apple.com>
+	* cp/cp-tree.h, cp/tree.c: New function non_cast_lvalue_p.
+	* cp/call.c: Change call-by-const-reference mechanism to use
+	non_cast_lvalue_p when deciding whether the create a temporary.
+	We need a temporary when passing, e.g. (long) x by const ref.
+	* testsuite/g++.dg/other/constref[12].C: New, regression tests for
+	passing a cast expression to a function by const reference.
+	
 2002-09-13  Richard Henderson  <rth@redhat.com>
 
 	* config/alpha/alpha.md (attr type): Add callpal.

gcc/cp/call.c

@@ -4059,7 +4059,7 @@ convert_like_real (convs, expr, fn, argnum, inner)
 	tree ref_type = totype;
 
 	/* If necessary, create a temporary.  */
-	if (NEED_TEMPORARY_P (convs) || !lvalue_p (expr))
+	if (NEED_TEMPORARY_P (convs) || !non_cast_lvalue_p (expr))
 	  {
 	    tree type = TREE_TYPE (TREE_OPERAND (convs, 0));
 	    expr = build_target_expr_with_type (expr, type);

gcc/cp/cp-tree.h

@@ -4184,6 +4184,7 @@ extern tree canonical_type_variant              PARAMS ((tree));
 extern void unshare_base_binfos			PARAMS ((tree));
 extern int member_p				PARAMS ((tree));
 extern cp_lvalue_kind real_lvalue_p		PARAMS ((tree));
+extern int non_cast_lvalue_p			PARAMS ((tree));
 extern int non_cast_lvalue_or_else		PARAMS ((tree, const char *));
 extern tree build_min				PARAMS ((enum tree_code, tree,
 							 ...));

gcc/cp/tree.c

@@ -229,6 +229,14 @@ lvalue_p (ref)
     (lvalue_p_1 (ref, /*class rvalue ok*/ 1, /*cast*/ 1) != clk_none);
 }
 
+int
+non_cast_lvalue_p (ref)
+     tree ref;
+{
+  return 
+    (lvalue_p_1 (ref, /*class rvalue ok*/ 1, /*cast*/ 0) != clk_none);
+}
+
 /* Return nonzero if REF is an lvalue valid for this language;
    otherwise, print an error message and return zero.  */
 

gcc/testsuite/g++.dg/other/constref1.C

+// { dg-do compile }
+
+// Copyright (C) 2002 Free Software Foundation, Inc.
+// Contributed by Matt Austern 12 Sep 2002 <austern@apple.com>
+
+// Make sure that we can pass a cast-expression as an argument that's
+// passed by const reference.
+
+void bar (const long&)
+{ }
+
+void foo (int x)
+{
+  bar ((long) x);
+}
+

gcc/testsuite/g++.dg/other/constref2.C

+// { dg-do compile }
+
+// Copyright (C) 2002 Free Software Foundation, Inc.
+// Contributed by Matt Austern 12 Sep 2002 <austern@apple.com>
+
+// Make sure that we can pass a cast-expression as an argument that's
+// passed to a function template by const reference.
+
+template <class T>
+void bar (const T&)
+{ }
+
+void foo (int x)
+{
+  bar ((long) x);
+}