float128: Add public _Float128 declarations to libm.

This introduces the machine-dependent bits/floatn.h to control
the inclusion of _Float128 ABI.

	* bits/floatn.h: New file.
	* bits/huge_val_flt128.h: Likewise.

	* bits/libm-simd-decl-stubs.h (__DECL_SIMD_cosf128): New macro.
	(__DECL_SIMD_sinf128): Likewise.
	(__DECL_SIMD_sincosf128): Likewise.
	(__DECL_SIMD_logf128): Likewise.
	(__DECL_SIMD_expf128): Likewise.
	(__DECL_SIMD_powf128): Likewise.

	* math/Makefile (headers): Install bits/floatn.h and
	bits/huge_val_flt128.h.

	* math/bits/cmathcalls.h (_Mdouble_complex_): Only define if not
	defined.

	* math/bits/mathcalls.h (pow10, isinf, finite, drem, significand)
	(isnan, gamma, nexttoward, scalb): Only define if not
	__MATH_DECLARING_FLOATN.
	(nextdown, nextup, llogb, roundeven, fromfp, ufromfp, fromfpx)
	(ufromfpx, fmaxmag, fminmag, totalorder, totalordermag)
	(canonicalize, getpayload, setpayload, setpayloadsig): Declare for
	_FloatN even if	__STDC_WANT_IEC_60559_BFP_EXT__ is not defined.

	* math/complex.h: Include bits/libc-header-start.h and bits/floatn.h.
	Include bits/cmathcalls.h to get the declarations of _Float128
	versions of complex functions.
	[__HAVE_FLOAT128 && __GLIBC_USE (IEC_60559_TYPES_EXT)] (CMPLXF128):
	Define macro.

	* math/math.h: Include bits/floatn.h and bits/huge_val_flt128.h.
	Include bits/mathcalls-helper-functions.h and bits/mathcalls.h to
	get the declarations of _Float128 versions of math functions.
	(__MATH_DECLARING_FLOATN): New macro to control declaration of
	_FloatN types.
	[__GNUC_PREREQ (6,0)] (signbit): Since GCC 6.0, __builtin_signbit
	is type-generic, so use it without __MATH_TG.
	[__HAVE_DISTINCT_FLOAT128] (isinf): This builtin is broken for
	_Float128 type on GCC < 7.0.  Explicitly call __isinff128 for
	_Float128 type and GCC < 7.0, otherwise use the builtin.
	[__HAVE_FLOAT128 && defined __USE_GNU] (M_Ef128, M_LOG2Ef128)
	(M_LOG10Ef128, M_LN2f128, M_LN10f128, M_PIf128, M_PI_2f128)
	(M_PI_4f128, M_1_PIf128, M_2_PIf128, M_SQRT2f128, M_SQRT1_2f128):
	New _GNU_SOURCE enabled macros.

1 files changed, 35 insertions, 0 deletions

diff --git a/bits/floatn.h b/bits/floatn.h
new file mode 100644
index 0000000000..a806496b87
--- /dev/null
+++ b/bits/floatn.h
@@ -0,0 +1,35 @@
+/* Macros to control TS 18661-3 glibc features.
+   Copyright (C) 2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Defined to 1 if the current compiler invocation provides a
+   floating-point type with the IEEE 754 binary128 format, and this glibc
+   includes corresponding *f128 interfaces for it.  */
+#define __HAVE_FLOAT128 0
+
+/* Defined to 1 if __HAVE_FLOAT128 is 1 and the type is ABI-distinct
+   from the default float, double and long double types in this glibc.  */
+#define __HAVE_DISTINCT_FLOAT128 0
+
+/* Defined to concatenate the literal suffix to be used with _Float128
+   types, if __HAVE_FLOAT128 is 1.
+   E.g.: #define __f128(x) x##f128.  */
+#undef __f128
+
+/* Defined to a complex binary128 type if __HAVE_FLOAT128 is 1.
+   E.g.: #define __CFLOAT128 _Complex _Float128.  */
+#undef __CFLOAT128