float128: Add private _Float128 declarations for libm.

Add the necessary bits to the private headers to support
building the _Float128 libm functions.

A local override for float.h is provided to include the
missing *FLT128 macros implied by TS 18661-3 for this
type when compiling prior to GCC 7.

	* include/complex.h (__kernel_casinhf128): New declaration.
	* include/float.h: New file.
	* include/math.h (__finitef128): Add a hidden def.
	(__isinff128): Likewise.
	(__isnanf128): Likewise.
	(__fpclassify): Likewise.
	(__issignalling): Likewise.
	(__expf128): Likewise.
	(__expm1f128): Likewise.

	* sysdeps/generic/fix-fp-int-convert-overflow.h:
	(FIX_FLT128_LONG_CONVERT_OVERFLOW): New macro.
	(FIX_FLT128_LLONG_CONVERT_OVERFLOW): Likewise.

	* sysdeps/generic/math-type-macros-float128.h: New file.

	* sysdeps/generic/math_private.h: Include bits/floatn.h and
	math_private_calls.h for _Float128.
	(__isinff128): New inline implementation used when GCC < 7.0,
	since in this case __builtin_isinf_sign is broken.
	(fabsf128): New inline implementation that calls the builtin.
	(__EXPR_FLT128): New macro.
	(min_of_type): Optionally include _Float128 types too.

	* sysdeps/generic/math_private_calls.h (__kernel_sincos):
	Declare for _Float128.
	(__kernel_rem_pio2): Likewise.

	* sysdeps/ieee754/ldbl-opt/s_sin.c:
	(__DECL_SIMD_sincos_disablef128): New macro.

3 files changed, 47 insertions, 0 deletions

diff --git a/include/complex.h b/include/complex.h
index 082e71fb10..2c86709ced 100644
--- a/include/complex.h
+++ b/include/complex.h
@@ -8,6 +8,9 @@
 extern complex float __kernel_casinhf (complex float z, int adj);
 extern complex double __kernel_casinh (complex double z, int adj);
 extern complex long double __kernel_casinhl (complex long double z, int adj);
+#  if __HAVE_DISTINCT_FLOAT128
+extern __CFLOAT128 __kernel_casinhf128 (__CFLOAT128 z, int adj);
+#  endif
 # endif
 
 #endif
diff --git a/include/float.h b/include/float.h
new file mode 100644
index 0000000000..20c4acbf78
--- /dev/null
+++ b/include/float.h
@@ -0,0 +1,31 @@
+#ifndef _LIBC_FLOAT_H
+#define _LIBC_FLOAT_H
+
+#ifndef _ISOMAC
+# define __STDC_WANT_IEC_60559_TYPES_EXT__
+#endif
+
+#include_next <float.h>
+
+/* Supplement float.h macros for _Float128 for older compilers
+   which do not yet support the type.  These are described in
+   TS 18661-3.  */
+#ifndef _ISOMAC
+# include <features.h>
+# include <bits/floatn.h>
+# if !__GNUC_PREREQ (7, 0) && __HAVE_DISTINCT_FLOAT128
+#  define FLT128_MANT_DIG	113
+#  define FLT128_DECIMAL_DIG	36
+#  define FLT128_DIG		33
+#  define FLT128_MIN_EXP	(-16381)
+#  define FLT128_MIN_10_EXP	(-4931)
+#  define FLT128_MAX_EXP	16384
+#  define FLT128_MAX_10_EXP	4932
+#  define FLT128_MAX		1.18973149535723176508575932662800702e+4932Q
+#  define FLT128_EPSILON	1.92592994438723585305597794258492732e-34Q
+#  define FLT128_MIN		3.36210314311209350626267781732175260e-4932Q
+#  define FLT128_TRUE_MIN	6.47517511943802511092443895822764655e-4966Q
+# endif
+#endif
+
+#endif /* _LIBC_FLOAT_H */
diff --git a/include/math.h b/include/math.h
index 6ff67830f8..a069680233 100644
--- a/include/math.h
+++ b/include/math.h
@@ -26,6 +26,12 @@ hidden_proto (__finitel)
 hidden_proto (__isinfl)
 hidden_proto (__isnanl)
 #  endif
+
+#  if __HAVE_DISTINCT_FLOAT128
+hidden_proto (__finitef128)
+hidden_proto (__isinff128)
+hidden_proto (__isnanf128)
+#  endif
 # endif
 
 libm_hidden_proto (__fpclassify)
@@ -43,5 +49,12 @@ libm_hidden_proto (__expl)
 libm_hidden_proto (__expm1l)
 # endif
 
+# if __HAVE_DISTINCT_FLOAT128
+libm_hidden_proto (__fpclassifyf128)
+libm_hidden_proto (__issignalingf128)
+libm_hidden_proto (__expf128)
+libm_hidden_proto (__expm1f128)
+# endif
+
 #endif
 #endif