re PR c++/52818 (printf format %lf is erroneously rejected by C++11)

	PR c++/52818
	* c-format.c (CPLUSPLUS_STD_VER): C++11 inherits from C99.
	(C_STD_NAME): Distinguish between C++98 and C++11.

From-SVN: r186468

gcc/c-family/ChangeLog

+2012-04-15  Jason Merrill  <jason@redhat.com>
+
+	PR c++/52818
+	* c-format.c (CPLUSPLUS_STD_VER): C++11 inherits from C99.
+	(C_STD_NAME): Distinguish between C++98 and C++11.
+
 2012-04-11  Eric Botcazou  <ebotcazou@adacore.com>
 
 	PR target/52624

gcc/c-family/c-format.c

@@ -334,7 +334,7 @@ decode_format_attr (tree args, function_format_info *info, int validated_p)
 
 /* The C standard version C++ is treated as equivalent to
    or inheriting from, for the purpose of format features supported.  */
-#define CPLUSPLUS_STD_VER	STD_C94
+#define CPLUSPLUS_STD_VER	(cxx_dialect < cxx11 ? STD_C94 : STD_C99)
 /* The C standard version we are checking formats against when pedantic.  */
 #define C_STD_VER		((int) (c_dialect_cxx ()		   \
 				 ? CPLUSPLUS_STD_VER			   \
@@ -345,7 +345,8 @@ decode_format_attr (tree args, function_format_info *info, int validated_p)
    pedantic.  FEATURE_VER is the version in which the feature warned out
    appeared, which is higher than C_STD_VER.  */
 #define C_STD_NAME(FEATURE_VER) (c_dialect_cxx ()		\
-				 ? "ISO C++"			\
+				 ? (cxx_dialect < cxx11 ? "ISO C++98" \
+				    : "ISO C++11")		\
 				 : ((FEATURE_VER) == STD_EXT	\
 				    ? "ISO C"			\
 				    : "ISO C90"))

gcc/testsuite/ChangeLog

+2012-04-15  Jason Merrill  <jason@redhat.com>
+
+	PR c++/52818
+	* g++.dg/warn/format8.C: New.
+
 2012-04-15  Janus Weil  <janus@gcc.gnu.org>
 
 	PR fortran/51082

gcc/testsuite/g++.dg/warn/format8.C

+// PR c++/52818
+// { dg-options "-pedantic-errors -Wformat" }
+
+extern "C" int printf (const char *, ...);
+void f() {
+  printf("%lf", 0.0);		// { dg-warning "%lf" "" { target c++98 } }
+}