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.

9 files changed, 230 insertions, 18 deletions

diff --git a/ChangeLog b/ChangeLog
index ece37e9d7e..22352418f4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,51 @@
+2017-05-14  Paul E. Murphy  <murphyp@linux.vnet.ibm.com>
+	    Gabriel F. T. Gomes  <gftg@linux.vnet.ibm.com>
+
+	* 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.
+
 2017-05-12  Joseph Myers  <joseph@codesourcery.com>
 
 	* sysdeps/sparc/sparc32/fpu/s_signbit.S (signbit): Remove alias.
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
diff --git a/bits/huge_val_flt128.h b/bits/huge_val_flt128.h
new file mode 100644
index 0000000000..63c258e85c
--- /dev/null
+++ b/bits/huge_val_flt128.h
@@ -0,0 +1,23 @@
+/* Default `HUGE_VAL_F128' constant.
+   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/>.  */
+
+#ifndef _MATH_H
+# error "Never use <bits/huge_val_flt128.h> directly; include <math.h> instead."
+#endif
+
+#define HUGE_VAL_F128 (__builtin_huge_valf128 ())
diff --git a/bits/libm-simd-decl-stubs.h b/bits/libm-simd-decl-stubs.h
index 7328eb2dd2..6794b9f9a8 100644
--- a/bits/libm-simd-decl-stubs.h
+++ b/bits/libm-simd-decl-stubs.h
@@ -36,24 +36,30 @@
 #define __DECL_SIMD_cos
 #define __DECL_SIMD_cosf
 #define __DECL_SIMD_cosl
+#define __DECL_SIMD_cosf128
 
 #define __DECL_SIMD_sin
 #define __DECL_SIMD_sinf
 #define __DECL_SIMD_sinl
+#define __DECL_SIMD_sinf128
 
 #define __DECL_SIMD_sincos
 #define __DECL_SIMD_sincosf
 #define __DECL_SIMD_sincosl
+#define __DECL_SIMD_sincosf128
 
 #define __DECL_SIMD_log
 #define __DECL_SIMD_logf
 #define __DECL_SIMD_logl
+#define __DECL_SIMD_logf128
 
 #define __DECL_SIMD_exp
 #define __DECL_SIMD_expf
 #define __DECL_SIMD_expl
+#define __DECL_SIMD_expf128
 
 #define __DECL_SIMD_pow
 #define __DECL_SIMD_powf
 #define __DECL_SIMD_powl
+#define __DECL_SIMD_powf128
 #endif
diff --git a/math/Makefile b/math/Makefile
index 634c6190c2..ff4aa0051b 100644
--- a/math/Makefile
+++ b/math/Makefile
@@ -29,7 +29,8 @@ headers		:= math.h bits/mathcalls.h bits/mathinline.h bits/huge_val.h \
 		   bits/math-finite.h bits/math-vector.h \
 		   bits/libm-simd-decl-stubs.h bits/iscanonical.h \
 		   bits/flt-eval-method.h bits/fp-fast.h bits/fp-logb.h \
-		   bits/long-double.h bits/mathcalls-helper-functions.h
+		   bits/long-double.h bits/mathcalls-helper-functions.h \
+		   bits/floatn.h bits/huge_val_flt128.h
 
 # FPU support code.
 aux		:= setfpucw fpu_control
diff --git a/math/bits/cmathcalls.h b/math/bits/cmathcalls.h
index 6e13930067..7f042dbeaa 100644
--- a/math/bits/cmathcalls.h
+++ b/math/bits/cmathcalls.h
@@ -44,7 +44,9 @@
 #error "Never use <bits/cmathcalls.h> directly; include <complex.h> instead."
 #endif
 
-#define _Mdouble_complex_ _Mdouble_ _Complex
+#ifndef _Mdouble_complex_
+# define _Mdouble_complex_ _Mdouble_ _Complex
+#endif
 
 
 /* Trigonometric functions.  */
diff --git a/math/bits/mathcalls.h b/math/bits/mathcalls.h
index 0d341fbfe1..90b996740b 100644
--- a/math/bits/mathcalls.h
+++ b/math/bits/mathcalls.h
@@ -115,7 +115,9 @@ __MATHCALL (exp10,, (_Mdouble_ __x));
 #endif
 #ifdef __USE_GNU
 /* Another name occasionally used.  */
+# if !__MATH_DECLARING_FLOATN
 __MATHCALL (pow10,, (_Mdouble_ __x));
+# endif
 #endif
 
 #if defined __USE_XOPEN_EXTENDED || defined __USE_ISOC99
@@ -172,14 +174,16 @@ __MATHCALLX (floor,, (_Mdouble_ __x), (__const__));
 __MATHCALL (fmod,, (_Mdouble_ __x, _Mdouble_ __y));
 
 #ifdef __USE_MISC
-# if (!defined __cplusplus \
-      || __cplusplus < 201103L /* isinf conflicts with C++11.  */ \
-      || __MATH_DECLARING_DOUBLE == 0) /* isinff or isinfl don't.  */
+# if ((!defined __cplusplus \
+       || __cplusplus < 201103L /* isinf conflicts with C++11.  */ \
+       || __MATH_DECLARING_DOUBLE == 0)) /* isinff or isinfl don't.  */ \
+      && !__MATH_DECLARING_FLOATN
 /* Return 0 if VALUE is finite or NaN, +1 if it
    is +Infinity, -1 if it is -Infinity.  */
 __MATHDECL_1 (int,isinf,, (_Mdouble_ __value)) __attribute__ ((__const__));
 # endif
 
+# if !__MATH_DECLARING_FLOATN
 /* Return nonzero if VALUE is finite and not NaN.  */
 __MATHDECL_1 (int,finite,, (_Mdouble_ __value)) __attribute__ ((__const__));
 
@@ -189,6 +193,8 @@ __MATHCALL (drem,, (_Mdouble_ __x, _Mdouble_ __y));
 
 /* Return the fractional part of X after dividing out `ilogb (X)'.  */
 __MATHCALL (significand,, (_Mdouble_ __x));
+# endif
+
 #endif /* Use misc.  */
 
 #ifdef __USE_ISOC99
@@ -203,9 +209,10 @@ __MATHCALLX (nan,, (const char *__tagb), (__const__));
 
 
 #if defined __USE_MISC || (defined __USE_XOPEN && !defined __USE_XOPEN2K)
-# if (!defined __cplusplus \
-      || __cplusplus < 201103L /* isnan conflicts with C++11.  */ \
-      || __MATH_DECLARING_DOUBLE == 0) /* isnanf or isnanl don't.  */
+# if ((!defined __cplusplus \
+       || __cplusplus < 201103L /* isnan conflicts with C++11.  */ \
+       || __MATH_DECLARING_DOUBLE == 0)) /* isnanf or isnanl don't.  */ \
+      && !__MATH_DECLARING_FLOATN
 /* Return nonzero if VALUE is not a number.  */
 __MATHDECL_1 (int,isnan,, (_Mdouble_ __value)) __attribute__ ((__const__));
 # endif
@@ -235,8 +242,10 @@ __MATHCALL (tgamma,, (_Mdouble_));
 #endif
 
 #if defined __USE_MISC || (defined __USE_XOPEN && !defined __USE_XOPEN2K)
+# if !__MATH_DECLARING_FLOATN
 /* Obsolete alias for `lgamma'.  */
 __MATHCALL (gamma,, (_Mdouble_));
+# endif
 #endif
 
 #ifdef __USE_MISC
@@ -254,11 +263,11 @@ __MATHCALL (rint,, (_Mdouble_ __x));
 
 /* Return X + epsilon if X < Y, X - epsilon if X > Y.  */
 __MATHCALLX (nextafter,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));
-# if defined __USE_ISOC99 && !defined __LDBL_COMPAT
+# if defined __USE_ISOC99 && !defined __LDBL_COMPAT && !__MATH_DECLARING_FLOATN
 __MATHCALLX (nexttoward,, (_Mdouble_ __x, long double __y), (__const__));
 # endif
 
-#if __GLIBC_USE (IEC_60559_BFP_EXT)
+# if __GLIBC_USE (IEC_60559_BFP_EXT) || __MATH_DECLARING_FLOATN
 /* Return X - epsilon.  */
 __MATHCALL (nextdown,, (_Mdouble_ __x));
 /* Return X + epsilon.  */
@@ -277,7 +286,7 @@ __MATHCALL (scalbn,, (_Mdouble_ __x, int __n));
 __MATHDECL (int,ilogb,, (_Mdouble_ __x));
 #endif
 
-#if __GLIBC_USE (IEC_60559_BFP_EXT)
+#if __GLIBC_USE (IEC_60559_BFP_EXT) || __MATH_DECLARING_FLOATN
 /* Like ilogb, but returning long int.  */
 __MATHDECL (long int, llogb,, (_Mdouble_ __x));
 #endif
@@ -332,7 +341,7 @@ __MATHCALLX (fmin,, (_Mdouble_ __x, _Mdouble_ __y), (__const__));
 __MATHCALL (fma,, (_Mdouble_ __x, _Mdouble_ __y, _Mdouble_ __z));
 #endif /* Use ISO C99.  */
 
-#if __GLIBC_USE (IEC_60559_BFP_EXT)
+#if __GLIBC_USE (IEC_60559_BFP_EXT) || __MATH_DECLARING_FLOATN
 /* Round X to nearest integer value, rounding halfway cases to even.  */
 __MATHCALLX (roundeven,, (_Mdouble_ __x), (__const__));
 
@@ -385,9 +394,10 @@ __MATHDECL_1 (int, setpayload,, (_Mdouble_ *__x, _Mdouble_ __payload));
 __MATHDECL_1 (int, setpayloadsig,, (_Mdouble_ *__x, _Mdouble_ __payload));
 #endif
 
-#if defined __USE_MISC || (defined __USE_XOPEN_EXTENDED \
-			   && __MATH_DECLARING_DOUBLE	\
-			   && !defined __USE_XOPEN2K8)
+#if (defined __USE_MISC || (defined __USE_XOPEN_EXTENDED \
+			    && __MATH_DECLARING_DOUBLE	  \
+			    && !defined __USE_XOPEN2K8))  \
+     && !__MATH_DECLARING_FLOATN
 /* Return X times (2 to the Nth power).  */
 __MATHCALL (scalb,, (_Mdouble_ __x, _Mdouble_ __n));
 #endif
diff --git a/math/complex.h b/math/complex.h
index 59ce30e297..1ae4ec2409 100644
--- a/math/complex.h
+++ b/math/complex.h
@@ -22,11 +22,15 @@
 #ifndef _COMPLEX_H
 #define _COMPLEX_H	1
 
-#include <features.h>
+#define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION
+#include <bits/libc-header-start.h>
 
 /* Get general and ISO C99 specific information.  */
 #include <bits/mathdef.h>
 
+/* Gather machine-dependent _FloatN type support.  */
+#include <bits/floatn.h>
+
 __BEGIN_DECLS
 
 /* We might need to add support for more compilers here.  But since ISO
@@ -55,6 +59,10 @@ __BEGIN_DECLS
 # define CMPLXL(x, y) __builtin_complex ((long double) (x), (long double) (y))
 #endif
 
+#if __HAVE_FLOAT128 && __GLIBC_USE (IEC_60559_TYPES_EXT)
+# define CMPLXF128(x, y) __builtin_complex ((_Float128) (x), (_Float128) (y))
+#endif
+
 /* The file <bits/cmathcalls.h> contains the prototypes for all the
    actual math functions.  These macros are used for those prototypes,
    so we can easily declare each function as both `name' and `__name',
@@ -84,6 +92,24 @@ __BEGIN_DECLS
 #undef	_Mdouble_
 #undef	__MATH_PRECNAME
 
+#if (__HAVE_DISTINCT_FLOAT128 || (__HAVE_FLOAT128 && !defined _LIBC)) \
+     && __GLIBC_USE (IEC_60559_TYPES_EXT)
+# ifndef _Mfloat128_
+#  define _Mfloat128_		_Float128
+# endif
+/* GCC < 7 requires extra convincing to expose a complex float128 type.  */
+# ifdef __CFLOAT128
+#  undef _Mdouble_complex_
+#  define _Mdouble_complex_	__CFLOAT128
+# endif
+# define _Mdouble_		_Mfloat128_
+# define __MATH_PRECNAME(name)	name##f128
+# include <bits/cmathcalls.h>
+# undef _Mdouble_
+# undef __MATH_PRECNAME
+# undef _Mdouble_complex_
+#endif
+
 /* And the long double versions.  It is non-critical to define them
    here unconditionally since `long double' is required in ISO C99.  */
 #if !(defined __NO_LONG_DOUBLE_MATH && defined _LIBC)	\
diff --git a/math/math.h b/math/math.h
index cfaed0ed98..daf58ab16a 100644
--- a/math/math.h
+++ b/math/math.h
@@ -34,9 +34,17 @@ __BEGIN_DECLS
 /* Get machine-dependent vector math functions declarations.  */
 #include <bits/math-vector.h>
 
+/* Gather machine dependent type support.  */
+#include <bits/floatn.h>
+
 /* Get machine-dependent HUGE_VAL value (returned on overflow).
    On all IEEE754 machines, this is +Infinity.  */
 #include <bits/huge_val.h>
+
+#if __HAVE_FLOAT128 && __GLIBC_USE (IEC_60559_TYPES_EXT)
+# include <bits/huge_val_flt128.h>
+#endif
+
 #ifdef __USE_ISOC99
 # include <bits/huge_valf.h>
 # include <bits/huge_vall.h>
@@ -208,11 +216,13 @@ enum
 #define _Mdouble_		double
 #define __MATH_PRECNAME(name,r)	__CONCAT(name,r)
 #define __MATH_DECLARING_DOUBLE  1
+#define __MATH_DECLARING_FLOATN  0
 #include <bits/mathcalls-helper-functions.h>
 #include <bits/mathcalls.h>
 #undef	_Mdouble_
 #undef	__MATH_PRECNAME
 #undef __MATH_DECLARING_DOUBLE
+#undef __MATH_DECLARING_FLOATN
 
 #ifdef __USE_ISOC99
 
@@ -226,11 +236,13 @@ enum
 # define _Mdouble_		_Mfloat_
 # define __MATH_PRECNAME(name,r) name##f##r
 # define __MATH_DECLARING_DOUBLE  0
+# define __MATH_DECLARING_FLOATN  0
 # include <bits/mathcalls-helper-functions.h>
 # include <bits/mathcalls.h>
 # undef	_Mdouble_
 # undef	__MATH_PRECNAME
 # undef __MATH_DECLARING_DOUBLE
+# undef __MATH_DECLARING_FLOATN
 
 # if !(defined __NO_LONG_DOUBLE_MATH && defined _LIBC) \
      || defined __LDBL_COMPAT \
@@ -269,16 +281,42 @@ extern long double __REDIRECT_NTH (nexttowardl,
 #  define _Mdouble_		_Mlong_double_
 #  define __MATH_PRECNAME(name,r) name##l##r
 #  define __MATH_DECLARING_DOUBLE  0
+#  define __MATH_DECLARING_FLOATN  0
 #  define __MATH_DECLARE_LDOUBLE   1
 #  include <bits/mathcalls-helper-functions.h>
 #  include <bits/mathcalls.h>
 #  undef _Mdouble_
 #  undef __MATH_PRECNAME
 #  undef __MATH_DECLARING_DOUBLE
+#  undef __MATH_DECLARING_FLOATN
 
 # endif /* !(__NO_LONG_DOUBLE_MATH && _LIBC) || __LDBL_COMPAT */
 
 #endif	/* Use ISO C99.  */
+
+/* Include the file of declarations again, this time using `_Float128'
+   instead of `double' and appending f128 to each function name.  */
+
+#if __HAVE_DISTINCT_FLOAT128 || (__HAVE_FLOAT128 && !defined _LIBC)
+# ifndef _Mfloat128_
+#  define _Mfloat128_		_Float128
+# endif
+# define _Mdouble_		_Mfloat128_
+# define __MATH_PRECNAME(name,r) name##f128##r
+# define __MATH_DECLARING_DOUBLE  0
+# define __MATH_DECLARING_FLOATN  1
+# if __HAVE_DISTINCT_FLOAT128
+#  include <bits/mathcalls-helper-functions.h>
+# endif
+# if __GLIBC_USE (IEC_60559_TYPES_EXT)
+#  include <bits/mathcalls.h>
+# endif
+# undef _Mdouble_
+# undef __MATH_PRECNAME
+# undef __MATH_DECLARING_DOUBLE
+# undef __MATH_DECLARING_FLOATN
+#endif /* __HAVE_DISTINCT_FLOAT128.  */
+
 #undef	__MATHDECL_1
 #undef	__MATHDECL
 #undef	__MATHCALL
@@ -348,7 +386,9 @@ enum
 # endif
 
 /* Return nonzero value if sign of X is negative.  */
-# if __GNUC_PREREQ (4,0)
+# if __GNUC_PREREQ (6,0)
+#  define signbit(x) __builtin_signbit (x)
+# elif __GNUC_PREREQ (4,0)
 #  define signbit(x) __MATH_TG ((x), __builtin_signbit, (x))
 # else
 #  define signbit(x) __MATH_TG ((x), __signbit, (x))
@@ -377,7 +417,13 @@ enum
 # endif
 
 /* Return nonzero value if X is positive or negative infinity.  */
-# if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__
+# if __HAVE_DISTINCT_FLOAT128 && !__GNUC_PREREQ (7,0) \
+     && !defined __SUPPORT_SNAN__
+   /* __builtin_isinf_sign is broken for float128 only before GCC 7.0.  */
+#  define isinf(x) \
+    (__builtin_types_compatible_p (__typeof (x), _Float128) \
+     ? __isinff128 (x) : __builtin_isinf_sign (x))
+# elif __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__
 #  define isinf(x) __builtin_isinf_sign (x)
 # else
 #  define isinf(x) __MATH_TG ((x), __isinf, (x))
@@ -529,6 +575,21 @@ extern int matherr (struct exception *__exc);
 # define M_SQRT1_2l	0.707106781186547524400844362104849039L /* 1/sqrt(2) */
 #endif
 
+#if __HAVE_FLOAT128 && defined __USE_GNU
+# define M_Ef128	__f128 (2.718281828459045235360287471352662498) /* e */
+# define M_LOG2Ef128	__f128 (1.442695040888963407359924681001892137) /* log_2 e */
+# define M_LOG10Ef128	__f128 (0.434294481903251827651128918916605082) /* log_10 e */
+# define M_LN2f128	__f128 (0.693147180559945309417232121458176568) /* log_e 2 */
+# define M_LN10f128	__f128 (2.302585092994045684017991454684364208) /* log_e 10 */
+# define M_PIf128	__f128 (3.141592653589793238462643383279502884) /* pi */
+# define M_PI_2f128	__f128 (1.570796326794896619231321691639751442) /* pi/2 */
+# define M_PI_4f128	__f128 (0.785398163397448309615660845819875721) /* pi/4 */
+# define M_1_PIf128	__f128 (0.318309886183790671537767526745028724) /* 1/pi */
+# define M_2_PIf128	__f128 (0.636619772367581343075535053490057448) /* 2/pi */
+# define M_2_SQRTPIf128	__f128 (1.128379167095512573896158903121545172) /* 2/sqrt(pi) */
+# define M_SQRT2f128	__f128 (1.414213562373095048801688724209698079) /* sqrt(2) */
+# define M_SQRT1_2f128	__f128 (0.707106781186547524400844362104849039) /* 1/sqrt(2) */
+#endif
 
 /* When compiling in strict ISO C compatible mode we must not use the
    inline functions since they, among other things, do not set the