glibc/sysdeps/x86/bits/floatn.h
Joseph Myers 3e5760fcb4 Update _FloatN header support for C++ in GCC 13
GCC 13 adds support for _FloatN and _FloatNx types in C++, so breaking
the installed glibc headers that assume such support is not present.
GCC mostly works around this with fixincludes, but that doesn't help
for building glibc and its tests (glibc doesn't itself contain C++
code, but there's C++ code built for tests).  Update glibc's
bits/floatn-common.h and bits/floatn.h headers to handle the GCC 13
support directly.

In general the changes match those made by fixincludes, though I think
the ones in sysdeps/powerpc/bits/floatn.h, where the header tests
__LDBL_MANT_DIG__ == 113 or uses #elif, wouldn't match the existing
fixincludes patterns.

Some places involving special C++ handling in relation to _FloatN
support are not changed.  There's no need to change the
__HAVE_FLOATN_NOT_TYPEDEF definition (also in a form that wouldn't be
matched by the fixincludes fixes) because it's only used in relation
to macro definitions using features not supported for C++
(__builtin_types_compatible_p and _Generic).  And there's no need to
change the inline function overloads for issignaling, iszero and
iscanonical in C++ because cases where types have the same format but
are no longer compatible types are handled automatically by the C++
overload resolution rules.

This patch also does not change the overload handling for iseqsig, and
there I think changes *are* needed, beyond those in this patch or made
by fixincludes.  The way that overload is defined, via a template
parameter to a structure type, requires overloads whenever the types
are incompatible, even if they have the same format.  So I think we
need to add overloads with GCC 13 for every supported _FloatN and
_FloatNx type, rather than just having one for _Float128 when it has a
different ABI to long double as at present (but for older GCC, such
overloads must not be defined for types that end up defined as
typedefs for another type).

Tested with build-many-glibcs.py: compilers build for
aarch64-linux-gnu ia64-linux-gnu mips64-linux-gnu powerpc-linux-gnu
powerpc64le-linux-gnu x86_64-linux-gnu; glibcs build for
aarch64-linux-gnu ia64-linux-gnu i686-linux-gnu mips-linux-gnu
mips64-linux-gnu-n32 powerpc-linux-gnu powerpc64le-linux-gnu
x86_64-linux-gnu.
2022-09-28 20:10:08 +00:00

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4.4 KiB
C

/* Macros to control TS 18661-3 glibc features on x86.
Copyright (C) 2017-2022 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
<https://www.gnu.org/licenses/>. */
#ifndef _BITS_FLOATN_H
#define _BITS_FLOATN_H
#include <features.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. The required
libgcc support was added some time after the basic compiler
support, for x86_64 and x86. */
#if (defined __x86_64__ \
? __GNUC_PREREQ (4, 3) \
: (defined __GNU__ ? __GNUC_PREREQ (4, 5) : __GNUC_PREREQ (4, 4)))
# 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 1 if the current compiler invocation provides a
floating-point type with the right format for _Float64x, and this
glibc includes corresponding *f64x interfaces for it. */
#define __HAVE_FLOAT64X 1
/* Defined to 1 if __HAVE_FLOAT64X is 1 and _Float64x has the format
of long double. Otherwise, if __HAVE_FLOAT64X is 1, _Float64x has
the format of _Float128, which must be different from that of long
double. */
#define __HAVE_FLOAT64X_LONG_DOUBLE 1
#ifndef __ASSEMBLER__
/* 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 && !__GNUC_PREREQ (13, 0))
/* The literal suffix f128 exists 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 && !__GNUC_PREREQ (13, 0))
/* Add a typedef for older GCC compilers which don't natively support
_Complex _Float128. */
typedef _Complex float __cfloat128 __attribute__ ((__mode__ (__TC__)));
# 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 exists only since GCC 7.0. */
# if !__GNUC_PREREQ (7, 0) || (defined __cplusplus && !__GNUC_PREREQ (13, 0))
typedef __float128 _Float128;
# endif
/* __builtin_huge_valf128 doesn't exist before GCC 7.0. */
# if !__GNUC_PREREQ (7, 0)
# define __builtin_huge_valf128() ((_Float128) __builtin_huge_val ())
# endif
/* Older GCC has only a subset of built-in functions for _Float128 on
x86, and __builtin_infq is not usable in static initializers.
Converting a narrower sNaN to _Float128 produces a quiet NaN, so
attempts to use _Float128 sNaNs will not work properly with older
compilers. */
# if !__GNUC_PREREQ (7, 0)
# define __builtin_copysignf128 __builtin_copysignq
# define __builtin_fabsf128 __builtin_fabsq
# define __builtin_inff128() ((_Float128) __builtin_inf ())
# define __builtin_nanf128(x) ((_Float128) __builtin_nan (x))
# define __builtin_nansf128(x) ((_Float128) __builtin_nans (x))
# 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
#endif /* !__ASSEMBLER__. */
#include <bits/floatn-common.h>
#endif /* _BITS_FLOATN_H */