re PR c/39037 (FLOAT_CONST_DECIMAL64 pragma not supported)

gcc/
	PR c/39037
	* c-common.h (mark_valid_location_for_stdc_pragma,
	valid_location_for_stdc_pragma_p, set_float_const_decimal64,
	clear_float_const_decimal64, float_const_decimal64_p): New.
	* c.opt (Wunsuffixed-float-constants): New.
	* c-lex.c (interpret_float): Use pragma FLOAT_CONST_DECIMAL64 for
	unsuffixed float constant, handle new warning.
	* c-cppbuiltin.c (c_cpp_builtins): Use cast for double constants.
	* c-decl.c (c_scope): New flag float_const_decimal64.
	(set_float_const_decimal64, clear_float_const_decimal64,
	float_const_decimal64_p): New.
	(push_scope): Set new flag.
	* c-parser.c (c_parser_translation_unit): Mark when it's valid
	to use STDC pragmas.
	(c_parser_external_declaration): Ditto.
	(c_parser_compound_statement_nostart): Ditto.
	* c-pragma.c (valid_location_for_stdc_pragma,
	mark_valid_location_for_stdc_pragma,
	valid_location_for_stdc_pragma_p, handle_stdc_pragma,
	handle_pragma_float_const_decimal64): New.
	(init_pragma): Register new pragma FLOAT_CONST_DECIMAL64.
	* cp/semantics.c (valid_location_for_stdc_pragma_p,
	set_float_const_decimal64, clear_float_const_decimal64,
	float_const_decimal64_p): New dummy functions.
	* doc/extend.texi (Decimal Float): Remove statement that the
	pragma, and suffix for double constants, are not supported.
	* doc/invoke.texi (Warning Options): List new option.
	(-Wunsuffixed-float-constants): New.

gcc/testsuite
	PR c/39037
	* gcc.dg/Wunsuffixed-float-constants-1.c: New test.
	* gcc.dg/cpp/pragma-float-const-decimal64-1.c: New test.
	* gcc.dg/dfp/float-constant-double.c: New test.
	* gcc.dg/dfp/pragma-float-const-decimal64-1.c: New test.
	* gcc.dg/dfp/pragma-float-const-decimal64-2.c: New test.
	* gcc.dg/dfp/pragma-float-const-decimal64-3.c: New test.
	* gcc.dg/dfp/pragma-float-const-decimal64-4.c: New test.
	* gcc.dg/dfp/pragma-float-const-decimal64-5.c: New test.
	* gcc.dg/dfp/pragma-float-const-decimal64-6.c: New test.
	* gcc.dg/dfp/pragma-float-const-decimal64-7.c: New test.
	* gcc.dg/dfp/pragma-float-const-decimal64-8.c: New test.
	* g++.dg/cpp/pragma-float-const-decimal64-1.C: New test.

From-SVN: r147259

24 files changed, 923 insertions, 15 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e1ffdd3..7d24caa 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,34 @@
+2009-05-07  Janis Johnson  <janis187@us.ibm.com>
+
+	PR c/39037
+	* c-common.h (mark_valid_location_for_stdc_pragma,
+	valid_location_for_stdc_pragma_p, set_float_const_decimal64,
+	clear_float_const_decimal64, float_const_decimal64_p): New.
+	* c.opt (Wunsuffixed-float-constants): New.
+	* c-lex.c (interpret_float): Use pragma FLOAT_CONST_DECIMAL64 for
+	unsuffixed float constant, handle new warning.
+	* c-cppbuiltin.c (c_cpp_builtins): Use cast for double constants.
+	* c-decl.c (c_scope): New flag float_const_decimal64.
+	(set_float_const_decimal64, clear_float_const_decimal64,
+	float_const_decimal64_p): New.
+	(push_scope): Set new flag.
+	* c-parser.c (c_parser_translation_unit): Mark when it's valid
+	to use STDC pragmas.
+	(c_parser_external_declaration): Ditto.
+	(c_parser_compound_statement_nostart): Ditto.
+	* c-pragma.c (valid_location_for_stdc_pragma,
+	mark_valid_location_for_stdc_pragma,
+	valid_location_for_stdc_pragma_p, handle_stdc_pragma,
+	handle_pragma_float_const_decimal64): New.
+	(init_pragma): Register new pragma FLOAT_CONST_DECIMAL64.
+	* cp/semantics.c (valid_location_for_stdc_pragma_p,
+	set_float_const_decimal64, clear_float_const_decimal64,
+	float_const_decimal64_p): New dummy functions.
+	* doc/extend.texi (Decimal Float): Remove statement that the
+	pragma, and suffix for double constants, are not supported.
+	* doc/invoke.texi (Warning Options): List new option.
+	(-Wunsuffixed-float-constants): New.
+
 2009-05-08  Steven Bosscher  <steven@gcc.gnu.org>
 
 	* config/i386/i386.c: Do not include c-common.h.
diff --git a/gcc/c-common.h b/gcc/c-common.h
index 1444880..250a7ff 100644
--- a/gcc/c-common.h
+++ b/gcc/c-common.h
@@ -809,6 +809,11 @@ extern void warn_logical_operator (location_t, enum tree_code,
 extern void check_main_parameter_types (tree decl);
 extern bool c_determine_visibility (tree);
 extern bool same_scalar_type_ignoring_signedness (tree, tree);
+extern void mark_valid_location_for_stdc_pragma (bool);
+extern bool valid_location_for_stdc_pragma_p (void);
+extern void set_float_const_decimal64 (void);
+extern void clear_float_const_decimal64 (void);
+extern bool float_const_decimal64_p (void);
 
 #define c_sizeof(T)  c_sizeof_or_alignof_type (T, true, 1)
 #define c_alignof(T) c_sizeof_or_alignof_type (T, false, 1)
diff --git a/gcc/c-cppbuiltin.c b/gcc/c-cppbuiltin.c
index 8b776b1..921addb 100644
--- a/gcc/c-cppbuiltin.c
+++ b/gcc/c-cppbuiltin.c
@@ -619,14 +619,11 @@ c_cpp_builtins (cpp_reader *pfile)
                                  TARGET_DEC_EVAL_METHOD);
 
   builtin_define_float_constants ("FLT", "F", "%s", float_type_node);
-  /* Cast the double precision constants when single precision constants are
-     specified. The correct result is computed by the compiler when using 
-     macros that include a cast. This has the side-effect of making the value 
-     unusable in const expressions. */
-  if (flag_single_precision_constant)
-    builtin_define_float_constants ("DBL", "L", "((double)%s)", double_type_node);
-  else
-    builtin_define_float_constants ("DBL", "", "%s", double_type_node);
+  /* Cast the double precision constants.  This is needed when single
+     precision constants are specified or when pragma FLOAT_CONST_DECIMAL64
+     is used.  The correct result is computed by the compiler when using
+     macros that include a cast.  */
+  builtin_define_float_constants ("DBL", "L", "((double)%s)", double_type_node);
   builtin_define_float_constants ("LDBL", "L", "%s", long_double_type_node);
 
   /* For decfloat.h.  */
diff --git a/gcc/c-decl.c b/gcc/c-decl.c
index 85c4d6b..409c458 100644
--- a/gcc/c-decl.c
+++ b/gcc/c-decl.c
@@ -342,6 +342,9 @@ struct GTY((chain_next ("%h.outer"))) c_scope {
 
   /* True means make a BLOCK for this scope no matter what.  */
   BOOL_BITFIELD keep : 1;
+
+  /* True means that an unsuffixed float constant is _Decimal64.  */
+  BOOL_BITFIELD float_const_decimal64 : 1;
 };
 
 /* The scope currently in effect.  */
@@ -674,6 +677,30 @@ keep_next_level (void)
   keep_next_level_flag = true;
 }
 
+/* Set the flag for the FLOAT_CONST_DECIMAL64 pragma being ON.  */
+
+void
+set_float_const_decimal64 (void)
+{
+  current_scope->float_const_decimal64 = true;
+}
+
+/* Clear the flag for the FLOAT_CONST_DECIMAL64 pragma.  */
+
+void
+clear_float_const_decimal64 (void)
+{
+  current_scope->float_const_decimal64 = false;
+}
+
+/* Return nonzero if an unsuffixed float constant is _Decimal64.  */
+
+bool
+float_const_decimal64_p (void)
+{
+  return current_scope->float_const_decimal64;
+}
+
 /* Identify this scope as currently being filled with parameters.  */
 
 void
@@ -705,6 +732,13 @@ push_scope (void)
 
       keep_next_level_flag = false;
       next_is_function_body = false;
+
+      /* The FLOAT_CONST_DECIMAL64 pragma applies to nested scopes.  */
+      if (current_scope->outer)
+	current_scope->float_const_decimal64
+	  = current_scope->outer->float_const_decimal64;
+      else
+	current_scope->float_const_decimal64 = false;
     }
   else
     {
@@ -717,6 +751,12 @@ push_scope (void)
       else
 	scope = GGC_CNEW (struct c_scope);
 
+      /* The FLOAT_CONST_DECIMAL64 pragma applies to nested scopes.  */
+      if (current_scope)
+	scope->float_const_decimal64 = current_scope->float_const_decimal64;
+      else
+	scope->float_const_decimal64 = false;
+
       scope->keep          = keep_next_level_flag;
       scope->outer         = current_scope;
       scope->depth	   = current_scope ? (current_scope->depth + 1) : 0;
diff --git a/gcc/c-lex.c b/gcc/c-lex.c
index df63548..fc89279 100644
--- a/gcc/c-lex.c
+++ b/gcc/c-lex.c
@@ -617,11 +617,21 @@ interpret_float (const cpp_token *token, unsigned int flags)
   char *copy;
   size_t copylen;
 
-  /* Default (no suffix) is double.  */
+  /* Default (no suffix) depends on whether the FLOAT_CONST_DECIMAL64
+     pragma has been used and is either double or _Decimal64.  Types
+     that are not allowed with decimal float default to double.  */
   if (flags & CPP_N_DEFAULT)
     {
       flags ^= CPP_N_DEFAULT;
       flags |= CPP_N_MEDIUM;
+
+      if (((flags & CPP_N_HEX) == 0) && ((flags & CPP_N_IMAGINARY) == 0))
+	{
+	  warning (OPT_Wunsuffixed_float_constants,
+		   "unsuffixed float constant");
+	  if (float_const_decimal64_p ())
+	    flags |= CPP_N_DFLOAT;
+	}
     }
 
   /* Decode _Fract and _Accum.  */
diff --git a/gcc/c-parser.c b/gcc/c-parser.c
index 6c839e9..033c835 100644
--- a/gcc/c-parser.c
+++ b/gcc/c-parser.c
@@ -976,6 +976,7 @@ c_parser_translation_unit (c_parser *parser)
   else
     {
       void *obstack_position = obstack_alloc (&parser_obstack, 0);
+      mark_valid_location_for_stdc_pragma (false);
       do
 	{
 	  ggc_collect ();
@@ -1060,7 +1061,9 @@ c_parser_external_declaration (c_parser *parser)
       c_parser_consume_token (parser);
       break;
     case CPP_PRAGMA:
+      mark_valid_location_for_stdc_pragma (true);
       c_parser_pragma (parser, pragma_external);
+      mark_valid_location_for_stdc_pragma (false);
       break;
     case CPP_PLUS:
     case CPP_MINUS:
@@ -3350,17 +3353,20 @@ c_parser_compound_statement_nostart (c_parser *parser)
 {
   bool last_stmt = false;
   bool last_label = false;
+  bool save_valid_for_pragma = valid_location_for_stdc_pragma_p ();
   location_t label_loc = UNKNOWN_LOCATION;  /* Quiet warning.  */
   if (c_parser_next_token_is (parser, CPP_CLOSE_BRACE))
     {
       c_parser_consume_token (parser);
       return;
     }
+  mark_valid_location_for_stdc_pragma (true);
   if (c_parser_next_token_is_keyword (parser, RID_LABEL))
     {
       location_t err_loc = c_parser_peek_token (parser)->location;
       /* Read zero or more forward-declarations for labels that nested
 	 functions can jump to.  */
+      mark_valid_location_for_stdc_pragma (false);
       while (c_parser_next_token_is_keyword (parser, RID_LABEL))
 	{
 	  c_parser_consume_token (parser);
@@ -3391,6 +3397,7 @@ c_parser_compound_statement_nostart (c_parser *parser)
   /* We must now have at least one statement, label or declaration.  */
   if (c_parser_next_token_is (parser, CPP_CLOSE_BRACE))
     {
+      mark_valid_location_for_stdc_pragma (save_valid_for_pragma);
       c_parser_error (parser, "expected declaration or statement");
       c_parser_consume_token (parser);
       return;
@@ -3409,12 +3416,14 @@ c_parser_compound_statement_nostart (c_parser *parser)
 	    label_loc = c_parser_peek_token (parser)->location;
 	  last_label = true;
 	  last_stmt = false;
+	  mark_valid_location_for_stdc_pragma (false);
 	  c_parser_label (parser);
 	}
       else if (!last_label
 	       && c_parser_next_token_starts_declspecs (parser))
 	{
 	  last_label = false;
+	  mark_valid_location_for_stdc_pragma (false);
 	  c_parser_declaration_or_fndef (parser, true, true, true, true);
 	  if (last_stmt)
 	    pedwarn_c90 (loc, 
@@ -3441,6 +3450,7 @@ c_parser_compound_statement_nostart (c_parser *parser)
 	      ext = disable_extension_diagnostics ();
 	      c_parser_consume_token (parser);
 	      last_label = false;
+	      mark_valid_location_for_stdc_pragma (false);
 	      c_parser_declaration_or_fndef (parser, true, true, true, true);
 	      /* Following the old parser, __extension__ does not
 		 disable this diagnostic.  */
@@ -3467,6 +3477,7 @@ c_parser_compound_statement_nostart (c_parser *parser)
 	}
       else if (c_parser_next_token_is (parser, CPP_EOF))
 	{
+	  mark_valid_location_for_stdc_pragma (save_valid_for_pragma);
 	  c_parser_error (parser, "expected declaration or statement");
 	  return;
 	}
@@ -3474,6 +3485,7 @@ c_parser_compound_statement_nostart (c_parser *parser)
         {
           if (parser->in_if_block) 
             {
+	      mark_valid_location_for_stdc_pragma (save_valid_for_pragma);
               error_at (loc, """expected %<}%> before %<else%>");
               return;
             }
@@ -3489,6 +3501,7 @@ c_parser_compound_statement_nostart (c_parser *parser)
 	statement:
 	  last_label = false;
 	  last_stmt = true;
+	  mark_valid_location_for_stdc_pragma (false);
 	  c_parser_statement_after_labels (parser);
 	}
 
@@ -3497,6 +3510,8 @@ c_parser_compound_statement_nostart (c_parser *parser)
   if (last_label)
     error_at (label_loc, "label at end of compound statement");
   c_parser_consume_token (parser);
+  /* Restore the value we started with.  */
+  mark_valid_location_for_stdc_pragma (save_valid_for_pragma);
 }
 
 /* Parse a label (C90 6.6.1, C99 6.8.1).
diff --git a/gcc/c-pragma.c b/gcc/c-pragma.c
index 64a224f..bd71d1d 100644
--- a/gcc/c-pragma.c
+++ b/gcc/c-pragma.c
@@ -1162,6 +1162,116 @@ handle_pragma_message (cpp_reader *ARG_UNUSED(dummy))
     inform (input_location, "#pragma message: %s", TREE_STRING_POINTER (message));
 }
 
+/* Mark whether the current location is valid for a STDC pragma.  */
+
+static bool valid_location_for_stdc_pragma;
+
+void
+mark_valid_location_for_stdc_pragma (bool flag)
+{
+  valid_location_for_stdc_pragma = flag;
+}
+
+/* Return true if the current location is valid for a STDC pragma.  */
+
+bool
+valid_location_for_stdc_pragma_p (void)
+{
+  return valid_location_for_stdc_pragma;
+}
+
+enum pragma_switch_t { ON, OFF, DEFAULT, BAD };
+
+/* A STDC pragma must appear outside of external declarations or
+   preceding all explicit declarations and statements inside a compound
+   statement; its behavior is undefined if used in any other context.
+   It takes a switch of ON, OFF, or DEFAULT.  */
+
+static enum pragma_switch_t
+handle_stdc_pragma (const char *pname)
+{
+  const char *arg;
+  tree t;
+  enum pragma_switch_t ret;
+
+  if (!valid_location_for_stdc_pragma_p ())
+    {
+      warning (OPT_Wpragmas, "invalid location for %<pragma %s%>, ignored",
+	       pname);
+      return BAD;
+    }
+
+  if (pragma_lex (&t) != CPP_NAME)
+    {
+      warning (OPT_Wpragmas, "malformed %<#pragma %s%>, ignored", pname);
+      return BAD;
+    }
+
+  arg = IDENTIFIER_POINTER (t);
+
+  if (!strcmp (arg, "ON"))
+    ret = ON;
+  else if (!strcmp (arg, "OFF"))
+    ret = OFF;
+  else if (!strcmp (arg, "DEFAULT"))
+    ret = DEFAULT;
+  else
+    {
+      warning (OPT_Wpragmas, "malformed %<#pragma %s%>, ignored", pname);
+      return BAD;
+    }
+
+  if (pragma_lex (&t) != CPP_EOF)
+    {
+      warning (OPT_Wpragmas, "junk at end of %<#pragma %s%>", pname);
+      return BAD;
+    }
+
+  return ret;
+}
+
+/* #pragma STDC FLOAT_CONST_DECIMAL64 ON
+   #pragma STDC FLOAT_CONST_DECIMAL64 OFF
+   #pragma STDC FLOAT_CONST_DECIMAL64 DEFAULT */
+
+static void
+handle_pragma_float_const_decimal64 (cpp_reader *ARG_UNUSED (dummy))
+{
+  if (c_dialect_cxx ())
+    {
+      if (warn_unknown_pragmas > in_system_header)
+	warning (OPT_Wunknown_pragmas,
+		 "%<#pragma STDC FLOAT_CONST_DECIMAL64%> is not supported"
+		 " for C++");
+      return;
+    }
+
+  if (!targetm.decimal_float_supported_p ())
+    {
+      if (warn_unknown_pragmas > in_system_header)
+	warning (OPT_Wunknown_pragmas,
+		 "%<#pragma STDC FLOAT_CONST_DECIMAL64%> is not supported"
+		 " on this target");
+      return;
+    }
+
+  pedwarn (input_location, OPT_pedantic,
+	   "ISO C does not support %<#pragma STDC FLOAT_CONST_DECIMAL64%>");
+
+  switch (handle_stdc_pragma ("STDC FLOAT_CONST_DECIMAL64"))
+    {
+    case ON:
+      set_float_const_decimal64 ();
+      break;
+    case OFF:
+    case DEFAULT:
+      clear_float_const_decimal64 ();
+      break;
+    case BAD:
+      break;
+    }
+}
+
 /* A vector of registered pragma callbacks.  */
 
 DEF_VEC_O (pragma_handler);
@@ -1330,6 +1440,9 @@ init_pragma (void)
   c_register_pragma ("GCC", "pop_options", handle_pragma_pop_options);
   c_register_pragma ("GCC", "reset_options", handle_pragma_reset_options);
 
+  c_register_pragma ("STDC", "FLOAT_CONST_DECIMAL64",
+		     handle_pragma_float_const_decimal64);
+
   c_register_pragma_with_expansion (0, "redefine_extname", handle_pragma_redefine_extname);
   c_register_pragma (0, "extern_prefix", handle_pragma_extern_prefix);
 
diff --git a/gcc/c.opt b/gcc/c.opt
index 7f71699..fc34ff5 100644
--- a/gcc/c.opt
+++ b/gcc/c.opt
@@ -476,6 +476,10 @@ Wunknown-pragmas
 C ObjC C++ ObjC++ Warning
 Warn about unrecognized pragmas
 
+Wunsuffixed-float-constants
+C ObjC Var(warn_unsuffixed_float_constants) Warning
+Warn about unsuffixed float constants
+
 Wunused-macros
 C ObjC C++ ObjC++ Warning
 Warn about macros defined in the main file that are not used
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index dd84891..4c0c91d 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -5050,4 +5050,23 @@ finish_trait_expr (cp_trait_kind kind, tree type1, tree type2)
 	  ? boolean_true_node : boolean_false_node);
 }
 
+/* Do-nothing variants of functions to handle pragma FLOAT_CONST_DECIMAL64,
+   which is ignored for C++.  */
+
+void
+set_float_const_decimal64 (void)
+{
+}
+
+void
+clear_float_const_decimal64 (void)
+{
+}
+
+bool
+float_const_decimal64_p (void)
+{
+  return 0;
+}
+
 #include "gt-cp-semantics.h"
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 4e06be3..43bebf9 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -958,10 +958,6 @@ is incomplete:
 
 @itemize @bullet
 @item
-Pragma @code{FLOAT_CONST_DECIMAL64} is not supported, nor is the @samp{d}
-suffix for literal constants of type @code{double}.
-
-@item
 When the value of a decimal floating type cannot be represented in the
 integer type to which it is being converted, the result is undefined
 rather than the result value specified by the draft technical report.
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 2674c47..3fc575d 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -259,8 +259,8 @@ Objective-C and Objective-C++ Dialects}.
 -Wswitch  -Wswitch-default  -Wswitch-enum -Wsync-nand @gol
 -Wsystem-headers  -Wtrigraphs  -Wtype-limits  -Wundef  -Wuninitialized @gol
 -Wunknown-pragmas  -Wno-pragmas -Wunreachable-code @gol
--Wunused  -Wunused-function  -Wunused-label  -Wunused-parameter @gol
--Wunused-value  -Wunused-variable @gol
+-Wunsuffixed-float-constants  -Wunused  -Wunused-function @gol
+-Wunused-label  -Wunused-parameter  -Wunused-value  -Wunused-variable @gol
 -Wvariadic-macros -Wvla @gol
 -Wvolatile-register-var  -Wwrite-strings}
 
@@ -4218,6 +4218,15 @@ minimum maximum, so we do not diagnose overlength strings in C++@.
 
 This option is implied by @option{-pedantic}, and can be disabled with
 @option{-Wno-overlength-strings}.
+
+@item -Wunsuffixed-float-constants
+@opindex Wunsuffixed-float-constants
+
+GCC will issue a warning for any floating constant that does not have
+a suffix.  When used together with @option{-Wsystem-headers} it will
+warn about such constants in system header files.  This can be useful
+when preparing code to use with the @code{FLOAT_CONST_DECIMAL64} pragma
+from the decimal floating-point extension to C99.
 @end table
 
 @node Debugging Options
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index eff2991..2dc3dd9 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,19 @@
+2009-05-07  Janis Johnson  <janis187@us.ibm.com>
+
+	PR c/39037
+	* gcc.dg/Wunsuffixed-float-constants-1.c: New test.
+	* gcc.dg/cpp/pragma-float-const-decimal64-1.c: New test.
+	* gcc.dg/dfp/float-constant-double.c: New test.
+	* gcc.dg/dfp/pragma-float-const-decimal64-1.c: New test.
+	* gcc.dg/dfp/pragma-float-const-decimal64-2.c: New test.
+	* gcc.dg/dfp/pragma-float-const-decimal64-3.c: New test.
+	* gcc.dg/dfp/pragma-float-const-decimal64-4.c: New test.
+	* gcc.dg/dfp/pragma-float-const-decimal64-5.c: New test.
+	* gcc.dg/dfp/pragma-float-const-decimal64-6.c: New test.
+	* gcc.dg/dfp/pragma-float-const-decimal64-7.c: New test.
+	* gcc.dg/dfp/pragma-float-const-decimal64-8.c: New test.
+	* g++.dg/cpp/pragma-float-const-decimal64-1.C: New test.
+
 2009-05-07  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/40057
diff --git a/gcc/testsuite/g++.dg/cpp/pragma-float-const-decimal64-1.C b/gcc/testsuite/g++.dg/cpp/pragma-float-const-decimal64-1.C
new file mode 100644
index 0000000..31e1ad6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp/pragma-float-const-decimal64-1.C
@@ -0,0 +1,5 @@
+// { dg-do compile }
+// { dg-options "-Wunknown-pragmas" }
+
+#pragma STDC FLOAT_CONST_DECIMAL64 ON	// { dg-warning "not supported for C\\\+\\\+" }
+double d = 1.0;
diff --git a/gcc/testsuite/gcc.dg/Wunsuffixed-float-constants-1.c b/gcc/testsuite/gcc.dg/Wunsuffixed-float-constants-1.c
new file mode 100644
index 0000000..b4a38d5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wunsuffixed-float-constants-1.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99 -Wunsuffixed-float-constants" } */
+
+#define VAL 0.5;
+
+double a = 1.1d;
+
+/* With FLOAT_CONST_DECIMAL64 switched to ON these would have type
+   _Decimal64.  */
+
+double b = VAL;		/* { dg-warning "unsuffixed float constant" } */
+double c = 1.2;		/* { dg-warning "unsuffixed float constant" } */
+
+/* With FLOAT_CONST_DECIMAL64 switched to ON these are still binary.  */
+
+double d = 0x5.0p1;	/* No warning for hex constant.  */
+double e = 3.1i;	/* No warning for imaginary constant.  */
diff --git a/gcc/testsuite/gcc.dg/cpp/pragma-float-const-decimal64-1.c b/gcc/testsuite/gcc.dg/cpp/pragma-float-const-decimal64-1.c
new file mode 100644
index 0000000..6333838
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/cpp/pragma-float-const-decimal64-1.c
@@ -0,0 +1,5 @@
+/* { dg-do compile { target { ! dfp } } } */
+/* { dg-options "-std=gnu99 -Wunknown-pragmas" } */
+
+#pragma STDC FLOAT_CONST_DECIMAL64 ON	/* { dg-warning "not supported on this target" } */
+double d = 1.0;
diff --git a/gcc/testsuite/gcc.dg/dfp/float-constant-double.c b/gcc/testsuite/gcc.dg/dfp/float-constant-double.c
new file mode 100644
index 0000000..3f8de65
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/dfp/float-constant-double.c
@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99" } */
+
+/* Constant float values of type double in <float.h> are suffixed with L
+   and cast to double so they can be used within code that uses pragma
+   FLOAT_CONST_DECIMAL64.  If they were not suffixed then use of the macro
+   would have them interpreted as _Decimal64, leading to errors when used
+   in expressions with other operands of type double.  */
+
+#include <float.h>
+
+extern double a, b, c, d;
+
+void
+foo ()
+{
+  _Pragma ("STDC FLOAT_CONST_DECIMAL64 ON")
+  a = 0.1d * DBL_MAX;
+  b = DBL_EPSILON * 10.0d;
+  c = DBL_MIN * 200.0d;
+}
diff --git a/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-1.c b/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-1.c
new file mode 100644
index 0000000..79fabf3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-1.c
@@ -0,0 +1,85 @@
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99 -Wall" } */
+
+/* N1312 7.1.1: The FLOAT_CONST_DECIMAL64 pragma.
+   C99 6.4.4.2a (New).
+
+   Verify that the pragma has the expected result by using unsuffixed
+   float constants as operands in expressions that would mix binary and
+   decimal operands if the pragma had no effect, or the wrong effect.  */
+
+#pragma STDC FLOAT_CONST_DECIMAL64 ON
+double a = 1.0 * 2.0dd;
+
+double
+f1 (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64 OFF
+  double b = 2.0 * 3.0d;
+
+  {
+    double c = 3.0 * 4.0d;
+    b = b + c;
+  }
+
+  {
+#pragma STDC FLOAT_CONST_DECIMAL64 ON
+    double d = 4.0 * 5.0dd;
+
+    b = b + d;
+  }
+
+  {
+     /* Default is OFF.  */
+#pragma STDC FLOAT_CONST_DECIMAL64 DEFAULT
+     double e = 5.0 * 6.0d;
+     b = b + e;
+  }
+
+  return b;
+}
+
+double
+f2 (void)
+{
+  /* Use value from outer scope, which is ON.  */
+  double b = 2.0 * 3.0dd;
+
+  {
+#pragma STDC FLOAT_CONST_DECIMAL64 OFF
+    double c = 3.0 * 4.0d;
+
+    {
+#pragma STDC FLOAT_CONST_DECIMAL64 ON
+      double d = 4.0 * 5.0dd;
+
+      {
+#pragma STDC FLOAT_CONST_DECIMAL64 DEFAULT
+	double e = 5.0 * 6.0d;
+
+	{
+#pragma STDC FLOAT_CONST_DECIMAL64 ON
+	  double f = 6.0 * 7.0dd;
+
+	  b = a + b + c + d + e + f;
+	}
+      }
+    }
+  }
+  return b;
+}
+
+/* Use previous value from this scope, which is ON.  */
+double f = 6.0 * 7.0dd;
+
+double
+f3 (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64 OFF
+  double b = 2.0 * 3.0d;
+
+  return b + f;
+}
+
+/* Return to the state from this scope, which is ON.  */
+double g = 7.0 + 8.0dd;
diff --git a/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-2.c b/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-2.c
new file mode 100644
index 0000000..212748c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-2.c
@@ -0,0 +1,86 @@
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99 -Wall" } */
+
+/* N1312 7.1.1: The FLOAT_CONST_DECIMAL64 pragma.
+   C99 6.4.4.2a (New).
+
+   Verify that the pragma has the expected result by using unsuffixed
+   float constants as operands in expressions that would mix binary and
+   decimal operands if the pragma had no effect, or the wrong effect.
+   Use _Pragma rather than #pragma.  */
+
+_Pragma ("STDC FLOAT_CONST_DECIMAL64 ON")
+double a = 1.0 * 2.0dd;
+
+double
+f1 (void)
+{
+_Pragma ("STDC FLOAT_CONST_DECIMAL64 OFF")
+  double b = 2.0 * 3.0d;
+
+  {
+    double c = 3.0 * 4.0d;
+    b = b + c;
+  }
+
+  {
+_Pragma ("STDC FLOAT_CONST_DECIMAL64 ON")
+    double d = 4.0 * 5.0dd;
+
+    b = b + d;
+  }
+
+  {
+     /* Default is OFF.  */
+_Pragma ("STDC FLOAT_CONST_DECIMAL64 DEFAULT")
+     double e = 5.0 * 6.0d;
+     b = b + e;
+  }
+
+  return b;
+}
+
+double
+f2 (void)
+{
+  /* Use value from outer scope, which is ON.  */
+  double b = 2.0 * 3.0dd;
+
+  {
+_Pragma ("STDC FLOAT_CONST_DECIMAL64 OFF")
+    double c = 3.0 * 4.0d;
+
+    {
+_Pragma ("STDC FLOAT_CONST_DECIMAL64 ON")
+      double d = 4.0 * 5.0dd;
+
+      {
+_Pragma ("STDC FLOAT_CONST_DECIMAL64 DEFAULT")
+	double e = 5.0 * 6.0d;
+
+	{
+_Pragma ("STDC FLOAT_CONST_DECIMAL64 ON")
+	  double f = 6.0 * 7.0dd;
+
+	  b = a + b + c + d + e + f;
+	}
+      }
+    }
+  }
+  return b;
+}
+
+/* Use previous value from this scope, which is ON.  */
+double f = 6.0 * 7.0dd;
+
+double
+f3 (void)
+{
+_Pragma ("STDC FLOAT_CONST_DECIMAL64 OFF")
+  double b = 2.0 * 3.0d;
+
+  return b + f;
+}
+
+/* Return to the state from this scope, which is ON.  */
+double g = 7.0 + 8.0dd;
diff --git a/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-3.c b/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-3.c
new file mode 100644
index 0000000..b9286aa
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-3.c
@@ -0,0 +1,83 @@
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99 -Wall" } */
+
+/* N1312 7.1.1: The FLOAT_CONST_DECIMAL64 pragma.
+   C99 6.4.4.2a (New).  */
+
+/* Check that defining macros whose names are the same as the tokens used
+   in the pragma doesn't affect use of the pragma.  */
+
+#define ON YES
+#define OFF NO
+#define DEFAULT NOPE
+#define STDC OFFICIAL
+#define FLOAT_CONST_DECIMAL64 NEW_PRAGMA
+
+double a;
+
+void
+f1a (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64 ON
+  a = 1.0dd + 2.0;
+}
+
+void
+f1b (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64 OFF
+  a = 2.0d + 3.0;
+}
+
+void
+f1c (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64 DEFAULT
+  a = 3.0d + 4.0;
+}
+
+/* Check that a macro can be used for the entire pragma.  */
+
+#define PRAGMA(x) _Pragma (#x)
+#define DEFAULT_FLOAT_IS_DECIMAL PRAGMA(STDC FLOAT_CONST_DECIMAL64 ON)
+#define DEFAULT_FLOAT_IS_BINARY PRAGMA(STDC FLOAT_CONST_DECIMAL64 OFF)
+
+void
+f2a (void)
+{
+  DEFAULT_FLOAT_IS_DECIMAL
+  a = 5.0 * 6.0dd;
+}
+
+void
+f2b (void)
+{
+  DEFAULT_FLOAT_IS_BINARY
+  a = 6.0 * 7.0d;
+}
+
+/* _Pragma can be used with macros, including the use of a macro for the
+    switch.  */
+
+#undef ON
+#undef OFF
+#undef DEFAULT
+#undef STDC
+#undef FLOAT_CONST_DECIMAL64
+
+#define SWITCH ON
+#define FLOAT_CONST_DECIMAL64(x) PRAGMA(STDC FLOAT_CONST_DECIMAL64 x)
+
+void
+f3a (void)
+{
+  FLOAT_CONST_DECIMAL64(SWITCH)
+  a = 1.0 * 7.0dd;
+}
+
+void
+f3b (void)
+{
+  FLOAT_CONST_DECIMAL64(OFF)
+  a = 1.0 + 2.0d;
+}
diff --git a/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-4.c b/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-4.c
new file mode 100644
index 0000000..86cec1d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-4.c
@@ -0,0 +1,46 @@
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99" } */
+
+/* N1312 7.1.1: The FLOAT_CONST_DECIMAL64 pragma.
+   C99 6.4.4.2a (New).
+
+   Check that malformed versions of pragma STDC FLOAT_CONST_DECIMAL64
+   are detected.  */
+
+double a;
+
+void f1 (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64	/* { dg-warning "malformed" } */
+  a = 1.0;
+}
+
+void f2 (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64 DFP	/* { dg-warning "malformed" } */
+  a = 2.0;
+}
+
+void f3 (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64 ON DFP /* { dg-warning "junk at end" } */
+  a = 3.0;
+}
+
+void f4 (void)
+{
+  _Pragma ( "STDC FLOAT_CONST_DECIMAL64" )	/* { dg-warning "malformed" } */
+  a = 1.0;
+}
+
+void f5 (void)
+{
+  _Pragma ( "STDC FLOAT_CONST_DECIMAL64 DFP" )	/* { dg-warning "malformed" } */
+  a = 2.0;
+}
+
+void f6 (void)
+{
+  _Pragma ( "STDC FLOAT_CONST_DECIMAL64 ON DFP" ) /* { dg-warning "junk at end" } */
+  a = 3.0;
+}
diff --git a/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-5.c b/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-5.c
new file mode 100644
index 0000000..75e9525
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-5.c
@@ -0,0 +1,46 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c99 -pedantic" } */
+
+/* N1312 7.1.1: The FLOAT_CONST_DECIMAL64 pragma.
+   C99 6.4.4.2a (New).
+
+   Check that there is a pedantic warning for the use of pragma
+   STD FLOAT_CONST_DECIMAL64.  */
+
+double a;
+
+void f1 (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64 ON		/* { dg-warning "ISO C" } */
+  a = 1.0;
+}
+
+void f2 (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64 OFF		/* { dg-warning "ISO C" } */
+  a = 2.0;
+}
+
+void f3 (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64 DEFAULT	/* { dg-warning "ISO C" } */
+  a = 3.0;
+}
+
+void f4 (void)
+{
+  _Pragma ("STDC FLOAT_CONST_DECIMAL64 ON")	/* { dg-warning "ISO C" } */
+  a = 1.0;
+}
+
+void f5 (void)
+{
+  _Pragma ("STDC FLOAT_CONST_DECIMAL64 OFF")	/* { dg-warning "ISO C" } */
+  a = 2.0;
+}
+
+void f6 (void)
+{
+  _Pragma ("STDC FLOAT_CONST_DECIMAL64 DEFAULT")	/* { dg-warning "ISO C" } */
+  a = 3.0;
+}
diff --git a/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-6.c b/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-6.c
new file mode 100644
index 0000000..03c1715
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-6.c
@@ -0,0 +1,46 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c99 -pedantic-errors" } */
+
+/* N1312 7.1.1: The FLOAT_CONST_DECIMAL64 pragma.
+   C99 6.4.4.2a (New).
+
+   Check that there is a pedantic error for the use of pragma
+   STD FLOAT_CONST_DECIMAL64.  */
+
+double a;
+
+void f1 (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64 ON		/* { dg-error "ISO C" } */
+  a = 1.0;
+}
+
+void f2 (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64 OFF		/* { dg-error "ISO C" } */
+  a = 2.0;
+}
+
+void f3 (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64 DEFAULT	/* { dg-error "ISO C" } */
+  a = 3.0;
+}
+
+void f4 (void)
+{
+  _Pragma ("STDC FLOAT_CONST_DECIMAL64 ON")	/* { dg-error "ISO C" } */
+  a = 1.0;
+}
+
+void f5 (void)
+{
+  _Pragma ("STDC FLOAT_CONST_DECIMAL64 OFF")	/* { dg-error "ISO C" } */
+  a = 2.0;
+}
+
+void f6 (void)
+{
+  _Pragma ("STDC FLOAT_CONST_DECIMAL64 DEFAULT") /* { dg-error "ISO C" } */
+  a = 3.0;
+}
diff --git a/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-7.c b/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-7.c
new file mode 100644
index 0000000..7533ee7
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-7.c
@@ -0,0 +1,39 @@
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99 -Wall" } */
+
+/* N1312 7.1.1: The FLOAT_CONST_DECIMAL64 pragma.
+   C99 6.4.4.2a (New).
+
+   Check that when pragma FLOAT_CONST_DECIMAL64 is in effect so that
+   unsuffixed constants are _Decimal64, invalid types are still reported
+   as invalid.  */
+
+double
+f1 (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64 OFF
+  double a = 0x1.0p1;
+  double b = 1.0i;
+
+  return a + b;
+}
+
+double
+f2 (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64 OFF
+  double a = 0x1.0p1dd;		/* { dg-error "with hex" } */
+  double b = 1.0idd;		/* { dg-error "invalid suffix" } */
+
+  return a + b;
+}
+
+double
+f3 (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64 ON
+  double a = 0x1.0p1;	/* Hex constant is not affected by pragma.  */
+  double b = 1.0i;	/* Imaginary constant is not affected by pragma.  */
+
+  return a + b;
+}
diff --git a/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-8.c b/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-8.c
new file mode 100644
index 0000000..5dbbda5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/dfp/pragma-float-const-decimal64-8.c
@@ -0,0 +1,174 @@
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99 -Wall" } */
+
+/* N1312 7.1.1: The FLOAT_CONST_DECIMAL64 pragma.
+   C99 6.4.4.2a (New).
+
+   Pragma STDC FLOAT_CONST_DECIMAL64 "shall occur either outside external
+   declarations or preceding all explicit declarations and statements
+   inside a compound statement." */
+
+#pragma STDC FLOAT_CONST_DECIMAL64 OFF
+
+#define MAX 200
+
+#pragma STDC FLOAT_CONST_DECIMAL64 ON
+
+double a;
+
+#pragma STDC FLOAT_CONST_DECIMAL64 OFF
+
+struct S1 {
+#pragma STDC FLOAT_CONST_DECIMAL64 ON	/* { dg-warning "invalid location" } */
+  int i;
+  int j;
+};
+
+struct S2 {
+  int i;
+#pragma STDC FLOAT_CONST_DECIMAL64 ON	/* { dg-warning "invalid location" } */
+  int j;
+};
+
+struct S3 {
+  int i;
+  int j;
+#pragma STDC FLOAT_CONST_DECIMAL64 ON	/* { dg-warning "invalid location" } */
+};
+
+enum E1 {
+#pragma STDC FLOAT_CONST_DECIMAL64 ON	/* { dg-error "#pragma" } */
+  one,
+  two
+};
+
+enum E2 {
+  red,
+#pragma STDC FLOAT_CONST_DECIMAL64 ON	/* { dg-error "#pragma" } */
+  blue
+};
+
+enum E3 {
+  cat,
+  dog
+#pragma STDC FLOAT_CONST_DECIMAL64 ON	/* { dg-error "#pragma" } */
+};
+
+double
+#pragma STDC FLOAT_CONST_DECIMAL64 OFF	/* { dg-error "#pragma" } */
+b;
+
+double
+f1 (void)
+{
+#pragma STDC FLOAT_CONST_DECIMAL64 ON
+  return a;
+}
+
+double
+f2 (void)
+{
+  double b;
+#pragma STDC FLOAT_CONST_DECIMAL64 ON	/* { dg-warning "invalid location" } */
+  b = 0.5;
+  return a + b;
+}
+
+#pragma STDC FLOAT_CONST_DECIMAL64 OFF
+
+double
+f3 (void)
+{
+  typedef double b32;
+#pragma STDC FLOAT_CONST_DECIMAL64 ON	/* { dg-warning "invalid location" } */
+  b32 b = 0.5;
+  return b;
+}
+
+double
+f4 (int i)
+{
+top:
+#pragma STDC FLOAT_CONST_DECIMAL64 OFF	/* { dg-warning "invalid location" } */
+  if (i == 0)
+    return a;  
+  a *= 2.;
+  i = 0;
+  goto top;
+}
+
+double
+f5 (int i)
+{
+  a = a * i;
+#pragma STDC FLOAT_CONST_DECIMAL64 OFF	/* { dg-warning "invalid location" } */
+  return a * 2.;
+}
+
+double
+#pragma STDC FLOAT_CONST_DECIMAL64 ON	/* { dg-error "#pragma" } */
+f6 (void)
+{
+  return a;
+}
+
+double
+f7
+#pragma STDC FLOAT_CONST_DECIMAL64 ON	/* { dg-error "#pragma" } */
+(void)					/* { dg-error "before" } */
+{
+  return a;
+}
+
+double
+f8 (void)
+{
+  {
+#pragma STDC FLOAT_CONST_DECIMAL64 OFF
+  }
+#pragma STDC FLOAT_CONST_DECIMAL64 ON   /* { dg-warning "invalid location" } */
+  return a;
+}
+
+extern void foo9 (void *);
+
+double
+f9 (void)
+{
+  __label__ here;
+#pragma STDC FLOAT_CONST_DECIMAL64 ON	/* { dg-warning "invalid location" } */
+  foo9 (&&here);
+here:
+  return a;
+}
+
+double
+f10 (void)
+{
+  void foo10 (void)
+  {
+    a = 1.0;
+  }
+#pragma STDC FLOAT_CONST_DECIMAL64 ON	/* { dg-warning "invalid location" } */
+  return a;
+}
+
+double
+f11 (void)
+{
+  __extension__
+   struct A {
+    struct { char a; };
+    char b;
+  };
+#pragma STDC FLOAT_CONST_DECIMAL64 ON	/* { dg-warning "invalid location" } */
+  return a;
+}
+
+double
+f12 (void)
+{
+  __extension__ ({ a = 0.5; });
+#pragma STDC FLOAT_CONST_DECIMAL64 ON	/* { dg-warning "invalid location" } */
+  return a;
+}