Add iszero.

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.

1 files changed, 1 insertions, 1 deletions

diff --git a/manual/libm-err-tab.pl b/manual/libm-err-tab.pl
index adeadb8f55..2386772b85 100755
--- a/manual/libm-err-tab.pl
+++ b/manual/libm-err-tab.pl
@@ -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) {