glibc/sysdeps/powerpc/bits/floatn.h
Joseph Myers 4e2dff67be Do not declare _Float128 support for powerpc64le -mlong-double-64 (bug 22402).
The powerpc bits/floatn.h declares _Float128 support to be present
when the compiler supports it for powerpc64le.  However, in the case
where -mlong-double-64 is used, __MATH_TG does not actually support
_Float128; it only supports _Float128 in the distinct-long-double
case.

This shows up as a build failure when building glibc mainline with GCC
mainline, given the recently added sanity check in math.h for
configurations supported by __MATH_TG, as the compat code for
-mlong-double-64 fails to build.  However, the bug was logically
present before that change (including in 2.26), just less visible.

This patch fixes the build failure by declaring _Float128 to be
unsupported in that case.  (Of course this can't actually stop users
calling the type-generic macros with _Float128 arguments with
-mlong-double-64, just as they could be called with other unsupported
types on other platforms, but perhaps makes it less likely by making
all the type-specific _Float128 interfaces invisible in that case.)

Tested compilation for powerpc64le with build-many-glibcs.py.

	[BZ #22402]
	* sysdeps/powerpc/bits/floatn.h: Include <bits/long-double.h>.
	[__NO_LONG_DOUBLE_MATH] (__HAVE_FLOAT128): Define to 0.
2017-11-06 13:26:15 +00:00

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C

/* Macros to control TS 18661-3 glibc features on powerpc.
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 _BITS_FLOATN_H
#define _BITS_FLOATN_H
#include <features.h>
#include <bits/long-double.h>
/* 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. */
#if defined _ARCH_PWR8 && defined __LITTLE_ENDIAN__ && (_CALL_ELF == 2) \
&& defined __FLOAT128__ && !defined __NO_LONG_DOUBLE_MATH
# define __HAVE_FLOAT128 1
#else
# define __HAVE_FLOAT128 0
#endif
/* 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. */
#if __HAVE_FLOAT128
# define __HAVE_DISTINCT_FLOAT128 1
#else
# define __HAVE_DISTINCT_FLOAT128 0
#endif
/* Defined to concatenate the literal suffix to be used with _Float128
types, if __HAVE_FLOAT128 is 1. */
#if __HAVE_FLOAT128
# if !__GNUC_PREREQ (7, 0) || defined __cplusplus
/* The literal suffix (f128) exist for powerpc only since GCC 7.0. */
# define __f128(x) x##q
# else
# define __f128(x) x##f128
# endif
#endif
/* Defined to a complex binary128 type if __HAVE_FLOAT128 is 1. */
#if __HAVE_FLOAT128
# if !__GNUC_PREREQ (7, 0) || defined __cplusplus
/* Add a typedef for older GCC compilers which don't natively support
_Complex _Float128. */
typedef _Complex float __cfloat128 __attribute__ ((__mode__ (__KC__)));
# define __CFLOAT128 __cfloat128
# else
# define __CFLOAT128 _Complex _Float128
# endif
#endif
/* The remaining of this file provides support for older compilers. */
#if __HAVE_FLOAT128
/* The type _Float128 exist for powerpc only since GCC 7.0. */
# if !__GNUC_PREREQ (7, 0) || defined __cplusplus
typedef __float128 _Float128;
# endif
/* Builtin __builtin_huge_valf128 doesn't exist before GCC 7.0. */
# if !__GNUC_PREREQ (7, 0)
# define __builtin_huge_valf128() ((_Float128) __builtin_huge_val ())
# endif
/* The following builtins (suffixed with 'q') are available in GCC >= 6.2,
which is the minimum version required for float128 support on powerpc64le.
Since GCC 7.0 the builtins suffixed with f128 are also available, then
there is no need to redefined them. */
# if !__GNUC_PREREQ (7, 0)
# define __builtin_copysignf128 __builtin_copysignq
# define __builtin_fabsf128 __builtin_fabsq
# define __builtin_inff128 __builtin_infq
# define __builtin_nanf128 __builtin_nanq
# define __builtin_nansf128 __builtin_nansq
# endif
/* In math/math.h, __MATH_TG will expand signbit to __builtin_signbit*,
e.g.: __builtin_signbitf128, before GCC 6. However, there has never
been a __builtin_signbitf128 in GCC and the type-generic builtin is
only available since GCC 6. */
# if !__GNUC_PREREQ (6, 0)
# define __builtin_signbitf128 __signbitf128
# endif
#endif
#include <bits/floatn-common.h>
#endif /* _BITS_FLOATN_H */