Add SNAN, SNANF, SNANL macros [committed]
Commit Message
TS 18661-1 defines SNAN macros for signaling NaN values, suitable for
use in static initializers. This patch adds them to glibc's <math.h>
(provided you are building with GCC 3.3 or later; no attempt is made
to provide any kind of nonconforming fallback for older compilers
without the __builtin_nans functions).
Tested for x86_64 and x86. Committed.
2016-10-28 Joseph Myers <joseph@codesourcery.com>
* math/math.h
[__GLIBC_USE (IEC_60559_BFP_EXT) && __GNUC_PREREQ (3, 3)] (SNANF):
New macro.
[__GLIBC_USE (IEC_60559_BFP_EXT) && __GNUC_PREREQ (3, 3)] (SNAN):
Likewise.
[__GLIBC_USE (IEC_60559_BFP_EXT) && __GNUC_PREREQ (3, 3)] (SNANL):
Likewise.
* manual/arith.texi (Infinity and NaN): Document SNANF, SNAN and
SNANL.
* math/test-double.h (snan_value_MACRO): New macro.
* math/test-float.h (snan_value_MACRO): Likewise.
* math/test-ldouble.h (snan_value_MACRO): Likewise.
* math/libm-test.inc (issignaling_test_data): Add tests of
snan_value_MACRO.
@@ -51,6 +51,8 @@ Version 2.25
* New <math.h> features are added from TS 18661-1:2014:
+ - Signaling NaN macros: SNANF, SNAN, SNANL.
+
- Comparison macros: iseqsig.
- Classification macros: iscanonical, issubnormal, iszero.
@@ -711,6 +711,15 @@ such as by defining @code{_GNU_SOURCE}, and then you must include
@file{math.h}.)
@end deftypevr
+@comment math.h
+@comment ISO
+@deftypevr Macro float SNANF
+@deftypevrx Macro double SNAN
+@deftypevrx Macro {long double} SNANL
+These macros, defined by TS 18661-1:2014, are constant expressions for
+signaling NaNs.
+@end deftypevr
+
@w{IEEE 754} also allows for another unusual value: negative zero. This
value is produced when you divide a positive number by negative
infinity, or when a negative result is smaller than the limits of
@@ -8901,6 +8901,8 @@ static const struct test_f_i_data issignaling_test_data[] =
TEST_f_b (issignaling, -qnan_value, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
TEST_f_b (issignaling, snan_value, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
TEST_f_b (issignaling, -snan_value, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+ TEST_f_b (issignaling, snan_value_MACRO, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+ TEST_f_b (issignaling, -snan_value_MACRO, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
};
static void
@@ -45,6 +45,15 @@ __BEGIN_DECLS
# include <bits/nan.h>
#endif /* __USE_ISOC99 */
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Signaling NaN macros, if supported. */
+# if __GNUC_PREREQ (3, 3)
+# define SNANF (__builtin_nansf (""))
+# define SNAN (__builtin_nans (""))
+# define SNANL (__builtin_nansl (""))
+# endif
+#endif
+
/* Get the architecture specific values describing the floating-point
evaluation. The following symbols will get defined:
@@ -27,3 +27,4 @@
#define TYPE_STR "double"
#define LITM(x) x
#define FTOSTR snprintf
+#define snan_value_MACRO SNAN
@@ -28,3 +28,4 @@
/* Use the double variants of macro constants. */
#define LITM(x) x
#define FTOSTR snprintf
+#define snan_value_MACRO SNANF
@@ -27,3 +27,4 @@
#define LIT(x) (x ## L)
#define LITM(x) x ## l
#define FTOSTR snprintf
+#define snan_value_MACRO SNANL