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Add iszero.

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TS 18661-1 adds an iszero classification macro to <math.h>.  This
patch implements it for glibc.  There are no new underlying functions
in libm because the implementation uses fpclassify when sNaN support
is required and a direct comparison otherwise; any optimizations for
this macro should be done through adding __builtin_iszero in GCC and
using it in the header for suitable GCC versions, not through adding
other optimized inline or out-of-line versions to glibc.

Tested for x86_64 and x86.

	* math/math.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (iszero): New
	macro.
	* math/libm-test.inc (iszero_test_data): New array.
	(iszero_test): New function.
	(main): Call iszero_test.
	* manual/arith.texi (Floating Point Classes): Document iszero.
	* manual/libm-err-tab.pl: Update comment on interfaces without
	ulps tabulated.
This commit is contained in:
Joseph Myers 2016-09-23 21:54:21 +00:00
parent 4775578486
commit bb8081f57f
6 changed files with 55 additions and 3 deletions
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11
ChangeLog
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@ -1,3 +1,14 @@
2016-09-23 Joseph Myers <joseph@codesourcery.com>
* math/math.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (iszero): New
macro.
* math/libm-test.inc (iszero_test_data): New array.
(iszero_test): New function.
(main): Call iszero_test.
* manual/arith.texi (Floating Point Classes): Document iszero.
* manual/libm-err-tab.pl: Update comment on interfaces without
ulps tabulated.
2016-09-23 Zack Weinberg <zackw@panix.com>
* scripts/check-installed-headers.sh: New script.

2
NEWS
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@ -51,7 +51,7 @@ Version 2.25
* New <math.h> features are added from TS 18661-1:2014:
- Classification macros: issubnormal.
- Classification macros: issubnormal, iszero.
* The <sys/quota.h> header now includes the <linux/quota.h> header. Support
for the Linux quota interface which predates kernel version 2.4.22 has

8
manual/arith.texi
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@ -414,6 +414,14 @@ This macro returns a nonzero value if @var{x} is subnormal. It is
from TS 18661-1:2014.
@end deftypefn
@comment math.h
@comment ISO
@deftypefn {Macro} int iszero (@emph{float-type} @var{x})
@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
This macro returns a nonzero value if @var{x} is zero. It is from TS
18661-1:2014.
@end deftypefn
Another set of floating-point classification functions was provided by
BSD. @Theglibc{} also supports these functions; however, we
recommend that you use the ISO C99 macros in new code. Those are standard

2
manual/libm-err-tab.pl
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@ -78,7 +78,7 @@ use vars qw (%results @all_floats %suffices @all_functions);
"scalbn", "sin", "sincos", "sinh", "sqrt", "tan", "tanh", "tgamma",
"trunc", "y0", "y1", "yn" );
# fpclassify, isnormal, isfinite, isinf, isnan, issignaling,
# issubnormal, signbit, isgreater, isgreaterequal, isless,
# issubnormal, iszero, signbit, isgreater, isgreaterequal, isless,
# islessequal, islessgreater, isunordered are not tabulated.
if ($#ARGV == 0) {

28
math/libm-test.inc
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@ -46,7 +46,7 @@
cbrt, ceil, copysign, cos, cosh, drem, erf, erfc, exp, exp10, exp2, expm1,
fabs, fdim, finite, floor, fma, fmax, fmin, fmod, fpclassify,
frexp, gamma, hypot,
ilogb, isfinite, isinf, isnan, isnormal, issignaling, issubnormal,
ilogb, isfinite, isinf, isnan, isnormal, issignaling, issubnormal, iszero,
isless, islessequal, isgreater, isgreaterequal, islessgreater, isunordered,
j0, j1, jn,
ldexp, lgamma, log, log10, log1p, log2, logb,
@ -8671,6 +8671,31 @@ isunordered_test (void)
ALL_RM_TEST (isunordered, 1, isunordered_test_data, RUN_TEST_LOOP_ff_i_tg, END);
}
static const struct test_f_i_data iszero_test_data[] =
{
TEST_f_b (iszero, 0, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
TEST_f_b (iszero, minus_zero, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
TEST_f_b (iszero, 10, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
TEST_f_b (iszero, min_subnorm_value, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
TEST_f_b (iszero, -min_subnorm_value, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
TEST_f_b (iszero, min_value, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
TEST_f_b (iszero, -min_value, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
TEST_f_b (iszero, max_value, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
TEST_f_b (iszero, -max_value, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
TEST_f_b (iszero, plus_infty, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
TEST_f_b (iszero, minus_infty, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
TEST_f_b (iszero, qnan_value, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
TEST_f_b (iszero, -qnan_value, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
TEST_f_b (iszero, snan_value, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
TEST_f_b (iszero, -snan_value, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
};
static void
iszero_test (void)
{
ALL_RM_TEST (iszero, 1, iszero_test_data, RUN_TEST_LOOP_f_b_tg, END);
}
static const struct test_f_f_data j0_test_data[] =
{
/* j0 is the Bessel function of the first kind of order 0 */
@ -12694,6 +12719,7 @@ main (int argc, char **argv)
isnormal_test ();
issignaling_test ();
issubnormal_test ();
iszero_test ();
signbit_test ();
/* Trigonometric functions: */

7
math/math.h
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@ -331,6 +331,13 @@ enum
/* Return nonzero value if X is subnormal. */
# define issubnormal(x) (fpclassify (x) == FP_SUBNORMAL)
/* Return nonzero value if X is zero. */
# ifdef __SUPPORT_SNAN__
# define iszero(x) (fpclassify (x) == FP_ZERO)
# else
# define iszero(x) ((x) == 0)
# endif
#endif /* Use IEC_60559_BFP_EXT. */
#ifdef __USE_MISC