PATCH to add -std=c++1y

[Jason Merrill <jason at redhat dot com>]

I've been working on a proposal for return type deduction for normal 
functions for the next C++ standard, and so I'm adding -std=c++1y to 
control it.

Tested x86_64-pc-linux-gnu, applying to trunk.
commit ef9ed182fec9249e396fdb0ed2bd0cc4d725e956
Author: Jason Merrill <jason@redhat.com>
Date:   Sat Mar 3 10:04:22 2012 -0500

    	* c-common.h (enum cxx_dialect): Add cxx1y.
    	* c-common.c (c_common_nodes_and_builtins): Use >= for cxx_dialect
    	test.
    	* c-cppbuiltin.c (c_cpp_builtins): Likewise.
    	* c-opts.c (c_common_post_options): Likewise.
    	(set_std_cxx1y): New.
    	(c_common_handle_option): Call it.
    	* c.opt (-std=c++1y, -std=gnu++1y): New flags.
    cp/
    	* lex.c (init_reswords): Use >= for cxx_dialect test.
    	* parser.c (cp_parser_exception_specification_opt): Likewise.
    testsuite/
    	* lib/target-supports.exp: Add { target c++1y }.

diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index b83f45b..fc83b04 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -4940,7 +4940,7 @@ c_common_nodes_and_builtins (void)
     {
       char16_type_node = make_unsigned_type (char16_type_size);
 
-      if (cxx_dialect == cxx0x)
+      if (cxx_dialect >= cxx0x)
 	record_builtin_type (RID_CHAR16, "char16_t", char16_type_node);
     }
 
@@ -4956,7 +4956,7 @@ c_common_nodes_and_builtins (void)
     {
       char32_type_node = make_unsigned_type (char32_type_size);
 
-      if (cxx_dialect == cxx0x)
+      if (cxx_dialect >= cxx0x)
 	record_builtin_type (RID_CHAR32, "char32_t", char32_type_node);
     }
 
diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
index 835b13b..8552f0c 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -649,7 +649,9 @@ enum cxx_dialect {
   cxx03 = cxx98,
   /* C++11  */
   cxx0x,
-  cxx11 = cxx0x
+  cxx11 = cxx0x,
+  /* C++1y (C++17?) */
+  cxx1y
 };
 
 /* The C++ dialect being used. C++98 is the default.  */
diff --git a/gcc/c-family/c-cppbuiltin.c b/gcc/c-family/c-cppbuiltin.c
index 40a0a62..49804f9 100644
--- a/gcc/c-family/c-cppbuiltin.c
+++ b/gcc/c-family/c-cppbuiltin.c
@@ -714,7 +714,7 @@ c_cpp_builtins (cpp_reader *pfile)
 	cpp_define (pfile, "__DEPRECATED");
       if (flag_rtti)
 	cpp_define (pfile, "__GXX_RTTI");
-      if (cxx_dialect == cxx0x)
+      if (cxx_dialect >= cxx0x)
         cpp_define (pfile, "__GXX_EXPERIMENTAL_CXX0X__");
     }
   /* Note that we define this for C as well, so that we know if
diff --git a/gcc/c-family/c-opts.c b/gcc/c-family/c-opts.c
index f2a7971..0ee4390 100644
--- a/gcc/c-family/c-opts.c
+++ b/gcc/c-family/c-opts.c
@@ -111,6 +111,7 @@ static size_t include_cursor;
 static void handle_OPT_d (const char *);
 static void set_std_cxx98 (int);
 static void set_std_cxx11 (int);
+static void set_std_cxx1y (int);
 static void set_std_c89 (int, int);
 static void set_std_c99 (int);
 static void set_std_c11 (int);
@@ -774,6 +775,12 @@ c_common_handle_option (size_t scode, const char *arg, int value,
 	set_std_cxx11 (code == OPT_std_c__11 /* ISO */);
       break;
 
+    case OPT_std_c__1y:
+    case OPT_std_gnu__1y:
+      if (!preprocessing_asm_p)
+	set_std_cxx1y (code == OPT_std_c__11 /* ISO */);
+      break;
+
     case OPT_std_c90:
     case OPT_std_iso9899_199409:
       if (!preprocessing_asm_p)
@@ -990,7 +997,7 @@ c_common_post_options (const char **pfilename)
   if (warn_implicit_function_declaration == -1)
     warn_implicit_function_declaration = flag_isoc99;
 
-  if (cxx_dialect == cxx0x)
+  if (cxx_dialect >= cxx0x)
     {
       /* If we're allowing C++0x constructs, don't warn about C++98
 	 identifiers which are keywords in C++0x.  */
@@ -1522,6 +1529,20 @@ set_std_cxx11 (int iso)
   cxx_dialect = cxx11;
 }
 
+/* Set the C++ 201y draft standard (without GNU extensions if ISO).  */
+static void
+set_std_cxx1y (int iso)
+{
+  cpp_set_lang (parse_in, iso ? CLK_CXX11: CLK_GNUCXX11);
+  flag_no_gnu_keywords = iso;
+  flag_no_nonansi_builtin = iso;
+  flag_iso = iso;
+  /* C++11 includes the C99 standard library.  */
+  flag_isoc94 = 1;
+  flag_isoc99 = 1;
+  cxx_dialect = cxx1y;
+}
+
 /* Args to -d specify what to dump.  Silently ignore
    unrecognized options; they may be aimed at toplev.c.  */
 static void
diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index 1ec5504..f785b60 100644
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -1215,6 +1215,10 @@ std=c++0x
 C++ ObjC++ Alias(std=c++11)
 Deprecated in favor of -std=c++11
 
+std=c++1y
+C++ ObjC++
+Conform to the ISO 201y(7?) C++ draft standard (experimental and incomplete support)
+
 std=c11
 C ObjC
 Conform to the ISO 2011 C standard (experimental and incomplete support)
@@ -1257,6 +1261,10 @@ std=gnu++0x
 C++ ObjC++ Alias(std=gnu++11)
 Deprecated in favor of -std=gnu++11
 
+std=gnu++1y
+C++ ObjC++
+Conform to the ISO 201y(7?) C++ draft standard with GNU extensions (experimental and incomplete support)
+
 std=gnu11
 C ObjC
 Conform to the ISO 2011 C standard with GNU extensions (experimental and incomplete support)
diff --git a/gcc/cp/lex.c b/gcc/cp/lex.c
index c11e3b3..a79448e 100644
--- a/gcc/cp/lex.c
+++ b/gcc/cp/lex.c
@@ -174,7 +174,7 @@ init_reswords (void)
   tree id;
   int mask = 0;
 
-  if (cxx_dialect != cxx0x)
+  if (cxx_dialect < cxx0x)
     mask |= D_CXX0X;
   if (flag_no_asm)
     mask |= D_ASM | D_EXT;
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index b3c87a8..75b7bdb 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -19594,7 +19594,7 @@ cp_parser_exception_specification_opt (cp_parser* parser)
 
 #if 0
   /* Enable this once a lot of code has transitioned to noexcept?  */
-  if (cxx_dialect == cxx0x && !in_system_header)
+  if (cxx_dialect >= cxx0x && !in_system_header)
     warning (OPT_Wdeprecated, "dynamic exception specifications are "
 	     "deprecated in C++0x; use %<noexcept%> instead");
 #endif
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index c744cb9..aae37bc 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -1597,20 +1597,36 @@ GNU dialect of ISO C11.  Support is incomplete and experimental.  The
 name @samp{gnu1x} is deprecated.
 
 @item c++98
-The 1998 ISO C++ standard plus amendments. Same as @option{-ansi} for
-C++ code.
+@itemx c++03
+The 1998 ISO C++ standard plus the 2003 technical corrigendum and some
+additional defect reports. Same as @option{-ansi} for C++ code.
 
 @item gnu++98
+@item gnu++03
 GNU dialect of @option{-std=c++98}.  This is the default for
 C++ code.
 
 @item c++11
+@item c++0x
 The 2011 ISO C++ standard plus amendments.  Support for C++11 is still
 experimental, and may change in incompatible ways in future releases.
+The name @samp{c++0x} is deprecated.
 
 @item gnu++11
+@item gnu++0x
 GNU dialect of @option{-std=c++11}. Support for C++11 is still
 experimental, and may change in incompatible ways in future releases.
+The name @samp{gnu++0x} is deprecated.
+
+@item c++1y
+The next revision of the ISO C++ standard, tentatively planned for
+2017.  Support is highly experimental, and will almost certainly
+change in incompatible ways in future releases.
+
+@item gnu++1y
+GNU dialect of @option{-std=c++1y}.  Support is highly experimental,
+and will almost certainly change in incompatible ways in future
+releases.
 @end table
 
 @item -fgnu89-inline
diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index b9a6601..23b6ea9 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -4431,11 +4431,18 @@ proc check_effective_target_c++11 { } {
     return [check-flags { { } { } { -std=c++0x -std=gnu++0x -std=c++11 -std=gnu++11 } }]
 }
 
+proc check_effective_target_c++1y { } {
+    if ![check_effective_target_c++] {
+	return 0
+    }
+    return [check-flags { { } { } { -std=c++1y -std=gnu++1y } }]
+}
+
 proc check_effective_target_c++98 { } {
     if ![check_effective_target_c++] {
 	return 0
     }
-    return [check-flags { { } { } { } { -std=c++0x -std=gnu++0x -std=c++11 -std=gnu++11 } }]
+    return [check-flags { { } { } { } { -std=c++0x -std=gnu++0x -std=c++11 -std=gnu++11 -std=c++1y -std=gnu++1y } }]
 }
 
 # Return 1 if expensive testcases should be run.