[committed] c: Do not use *_IS_IEC_60559 == 2

[Joseph Myers <joseph@codesourcery.com>]

A late change for C2x (addressing comments from the second round of
editorial review before the CD ballot, postdating the most recent
public working draft) removed the value 2 for *_IS_IEC_60559 (a new
<float.h> macro added in C2x).  Adjust the implementation accordingly
not to use this value.

Bootstrapped with no regressions for x86_64-pc-linux-gnu.

gcc/
	* ginclude/float.h (FLT_IS_IEC_60559, DBL_IS_IEC_60559)
	(LDBL_IS_IEC_60559): Update comment.

gcc/c-family/
	* c-cppbuiltin.cc (builtin_define_float_constants): Do not use
	value 2 for *_IS_IEC_60559.

gcc/testsuite/
	* gcc.dg/c2x-float-10.c: Do not expect value 2 for *_IS_IEC_60559.

diff --git a/gcc/c-family/c-cppbuiltin.cc b/gcc/c-family/c-cppbuiltin.cc
index 4b8486c8879..2e39acb9239 100644
--- a/gcc/c-family/c-cppbuiltin.cc
+++ b/gcc/c-family/c-cppbuiltin.cc
@@ -319,14 +319,10 @@ builtin_define_float_constants (const char *name_prefix,
     }
 
   /* For C2x *_IS_IEC_60559.  0 means the type does not match an IEC
-     60559 format, 1 that it matches a format but not operations and 2
-     that it matches a format and operations (but may not conform to
-     Annex F; we take this as meaning exceptions and rounding modes
-     need not be supported).  */
+     60559 format, 1 that it matches a format but not necessarily
+     operations.  */
   sprintf (name, "__%s_IS_IEC_60559__", name_prefix);
-  builtin_define_with_int_value (name,
-				 (fmt->ieee_bits == 0
-				  ? 0 : (fmt->round_towards_zero ? 1 : 2)));
+  builtin_define_with_int_value (name, fmt->ieee_bits != 0);
 }
 
 /* Define __DECx__ constants for TYPE using NAME_PREFIX and SUFFIX. */
diff --git a/gcc/ginclude/float.h b/gcc/ginclude/float.h
index afe4a712878..bc5439d664f 100644
--- a/gcc/ginclude/float.h
+++ b/gcc/ginclude/float.h
@@ -248,8 +248,7 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define DBL_NORM_MAX	__DBL_NORM_MAX__
 #define LDBL_NORM_MAX	__LDBL_NORM_MAX__
 
-/* Whether each type matches an IEC 60559 format (1 for format, 2 for
-   format and operations).  */
+/* Whether each type matches an IEC 60559 format.  */
 #undef FLT_IS_IEC_60559
 #undef DBL_IS_IEC_60559
 #undef LDBL_IS_IEC_60559
diff --git a/gcc/testsuite/gcc.dg/c2x-float-10.c b/gcc/testsuite/gcc.dg/c2x-float-10.c
index 7b53a6ab050..7206921db87 100644
--- a/gcc/testsuite/gcc.dg/c2x-float-10.c
+++ b/gcc/testsuite/gcc.dg/c2x-float-10.c
@@ -21,13 +21,13 @@ _Static_assert (FLT_IS_IEC_60559 == 0);
 _Static_assert (DBL_IS_IEC_60559 == 0);
 _Static_assert (LDBL_IS_IEC_60559 == 0);
 #else
-_Static_assert (FLT_IS_IEC_60559 == 2);
-_Static_assert (DBL_IS_IEC_60559 == 2);
+_Static_assert (FLT_IS_IEC_60559 == 1);
+_Static_assert (DBL_IS_IEC_60559 == 1);
 #if LDBL_MANT_DIG == 106 || LDBL_MIN_EXP == -16382
 /* IBM long double and m68k extended format do not meet the definition
    of an IEC 60559 interchange or extended format.  */
 _Static_assert (LDBL_IS_IEC_60559 == 0);
 #else
-_Static_assert (LDBL_IS_IEC_60559 == 2);
+_Static_assert (LDBL_IS_IEC_60559 == 1);
 #endif
 #endif

-- 
Joseph S. Myers
joseph@codesourcery.com