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.
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.
I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah. I don't
know why I run into these diagnostics whereas others evidently do not.
remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 6694 files FOO.
I then removed trailing white space from benchtests/bench-pthread-locks.c
and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this
diagnostic from Savannah:
remote: *** pre-commit check failed ...
remote: *** error: lines with trailing whitespace found
remote: error: hook declined to update refs/heads/master
This patch continues filling out TS 18661-3 support by adding *f64x
function aliases on platforms with _Float64x support. (It so happens
the set of such platforms is exactly the same as the set of platforms
with _Float128 support, although on x86_64, x86 and ia32 the _Float64x
format is Intel extended rather than binary128.) The API provided
corresponds exactly to that provided for _Float128, mostly coming from
TS 18661-3. As these functions always alias those for another type
(long double, _Float128 or both), __* function names are not provided,
as in other cases of alias types.
Given the preparation done in previous patches, this one just enables
the feature via Makeconfig and bits/floatn.h, adds symbol versions,
and updates documentation and ABI baselines. The symbol versions are
present unconditionally as GLIBC_2.27 in the relevant Versions files,
as it's OK for those to specify versions for functions that may not be
present in some configurations; no additional complexity is needed
unless in future some configuration gains support for this type that
didn't have such support in 2.27. The Makeconfig additions for ia64
and x86 aren't strictly needed, as those configurations also get
float64x-alias-fcts definitions from
sysdeps/ieee754/float128/Makeconfig, but still seem appropriate given
that _Float64x is not _Float128 for those configurations.
A libm-test-ulps update for x86 is included. This is because
bits/mathinline.h does not have _Float64x support added and for two
functions the use of out-of-line functions results in increased ulps
(ifloat64x shares ulps with ildouble / ifloat128 as appropriate).
Given that we'd like generally to eliminate bits/mathinline.h
optimizations, preferring to have such optimizations in GCC instead,
it seems reasonable not to add such support there for new types. GCC
support for _FloatN / _FloatNx built-in functions is limited, but has
been improved in GCC 8, and at some point I hope the full set of libm
built-in functions in GCC, and other optimizations with
per-floating-type aspects, will be enabled for all _FloatN / _FloatNx
types.
Tested for x86_64 and x86, and with build-many-glibcs.py, with both
GCC 6 and GCC 7.
* sysdeps/ia64/Makeconfig (float64x-alias-fcts): New variable.
* sysdeps/ieee754/float128/Makeconfig (float64x-alias-fcts):
Likewise.
* sysdeps/ieee754/ldbl-128/Makeconfig (float64x-alias-fcts):
Likewise.
* sysdeps/x86/Makeconfig: New file.
* bits/floatn-common.h (__HAVE_FLOAT64X): Remove macro.
(__HAVE_FLOAT64X_LONG_DOUBLE): Likewise.
* bits/floatn.h (__HAVE_FLOAT64X): New macro.
(__HAVE_FLOAT64X_LONG_DOUBLE): Likewise.
* sysdeps/ia64/bits/floatn.h (__HAVE_FLOAT64X): Likewise.
(__HAVE_FLOAT64X_LONG_DOUBLE): Likewise.
* sysdeps/ieee754/ldbl-128/bits/floatn.h (__HAVE_FLOAT64X):
Likewise.
(__HAVE_FLOAT64X_LONG_DOUBLE): Likewise.
* sysdeps/mips/ieee754/bits/floatn.h (__HAVE_FLOAT64X): Likewise.
(__HAVE_FLOAT64X_LONG_DOUBLE): Likewise.
* sysdeps/powerpc/bits/floatn.h (__HAVE_FLOAT64X): Likewise.
(__HAVE_FLOAT64X_LONG_DOUBLE): Likewise.
* sysdeps/x86/bits/floatn.h (__HAVE_FLOAT64X): Likewise.
(__HAVE_FLOAT64X_LONG_DOUBLE): Likewise.
* manual/math.texi (Mathematics): Document support for _Float64x.
* math/Versions (GLIBC_2.27): Add _Float64x functions.
* stdlib/Versions (GLIBC_2.27): Likewise.
* wcsmbs/Versions (GLIBC_2.27): Likewise.
* sysdeps/unix/sysv/linux/aarch64/libc.abilist: Update.
* sysdeps/unix/sysv/linux/aarch64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/alpha/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/alpha/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/i386/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/i386/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/ia64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/ia64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist:
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Likewise.
* sysdeps/i386/fpu/libm-test-ulps: Likewise.
* sysdeps/i386/i686/fpu/multiarch/libm-test-ulps: Likewise.
Further _FloatN / _FloatNx type alias support will involve making
architecture-specific .S files use the common macros for libm function
aliases. Making them use those macros will also serve to simplify
existing code for aliases / symbol versions in various cases, similar
to such simplifications for ldbl-opt code.
The libm-alias-*.h files sometimes need to include <bits/floatn.h> to
determine which aliases they should define. At present, this does not
work for inclusion from .S files because <bits/floatn.h> can define
typedefs for old compilers. This patch changes all the
<bits/floatn.h> and <bits/floatn-common.h> headers to include
__ASSEMBLER__ conditionals. Those conditionals disable everything
related to C syntax in the __ASSEMBLER__ case, not just the problem
typedefs, as that seemed cleanest. The __HAVE_* definitions remain in
the __ASSEMBLER__ case, as those provide information that is required
to define the correct set of aliases.
Tested with build-many-glibcs.py for a representative set of
configurations (x86_64-linux-gnu i686-linux-gnu ia64-linux-gnu
powerpc64le-linux-gnu mips64-linux-gnu-n64 sparc64-linux-gnu) with GCC
6. Also tested with GCC 6 for i686-linux-gnu in conjunction with
changes to use alias macros in .S files.
* bits/floatn-common.h [!__ASSEMBLER]: Disable everything related
to C syntax instead of availability and properties of types.
* bits/floatn.h [!__ASSEMBLER]: Likewise.
* sysdeps/ia64/bits/floatn.h [!__ASSEMBLER]: Likewise.
* sysdeps/ieee754/ldbl-128/bits/floatn.h [!__ASSEMBLER]: Likewise.
* sysdeps/mips/ieee754/bits/floatn.h [!__ASSEMBLER]: Likewise.
* sysdeps/powerpc/bits/floatn.h [!__ASSEMBLER]: Likewise.
* sysdeps/x86/bits/floatn.h [!__ASSEMBLER]: Likewise.
The bits/floatn.h header currently only has defines relating to
_Float128. This patch adds defines relating to other _FloatN /
_FloatNx types.
The approach taken is to add defines for all _FloatN / _FloatNx types
known to GCC, and to put them in a common bits/floatn-common.h header
included at the end of all the individual bits/floatn.h headers. If
in future some defines become different for different glibc
configurations, they will move out into the separate bits/floatn.h
headers.
Some defines are expected always to be the same across glibc ports.
Corresponding defines are nevertheless put in this header. The intent
is that where there are conditionals (in headers or in non-installed
files) that can just repeat the same or nearly the same logic for each
floating-point type, they should do so, even if in fact the cases for
some types could be unconditionally present or absent because the same
conditionals are true or false for all glibc configurations. This
should make the glibc code with such conditionals easier to read,
because the reader can just see that the same conditionals are
repeated for each type, rather than seeing different conditionals for
different types and needing to reason, at each location with such
differences, why those differences are indeed correct there. (Cases
involving per-format rather than per-type logic are more likely still
to need differences in how they handle different types.)
Having such defines and conditionals also helps in incremental
preparation for adding _Float32 / _Float64 / _Float32x / _Float64x
function aliases. I intend subsequent patches to add such
conditionals corresponding to those already present for _Float128, as
well as making more architecture-specific function implementations use
common macros to define aliases in preparation for adding such _FloatN
/ _FloatNx aliases.
Tested for x86_64.
* bits/floatn-common.h: New file.
* math/Makefile (headers): Add bits/floatn-common.h.
* bits/floatn.h: Include <bits/floatn-common.h>.
* sysdeps/ia64/bits/floatn.h: Likewise.
* sysdeps/ieee754/ldbl-128/bits/floatn.h: Likewise.
* sysdeps/mips/ieee754/bits/floatn.h: Likewise.
* sysdeps/powerpc/bits/floatn.h: Likewise.
* sysdeps/x86/bits/floatn.h: Likewise.
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. For older GCC, this patch defines
__builtin_signbitf128 to __signbitf128, so that the internal function
is used instead of the non-existent builtin.
This patch also changes the implementation of __signbitf128, because
it was reusing the implementation of __signbitl from ldbl-128, which
calls __builtin_signbitl. Using the long double version of the
builtin is not correct on machines where _Float128 is ABI-distinct
from long double (i.e.: ia64, powerpc64le, x86, x86_84). The new
implementation does not rely on builtins when being built with GCC
versions older than 6.0.
The new code does not currently affect powerpc64le builds, because
only GCC 6.2 fulfills the requirements from configure. It might
affect powerpc64le builds if those requirements are backported to
older versions of the compiler. The new code affects x86_64 builds,
since glibc is supposed to build correctly with older versions of GCC.
Tested for powerpc64le and x86_64.
* include/math.h (__signbitf128): Define as hidden.
* sysdeps/ieee754/float128/s_signbitf128.c (__signbitf128):
Reimplement without builtins.
* sysdeps/ia64/bits/floatn.h [!__GNUC_PREREQ (6, 0)]
(__builtin_signbitf128): Define to __signbitf128.
* sysdeps/powerpc/bits/floatn.h: Likewise.
* sysdeps/x86/bits/floatn.h: Likewise.
This patch enables float128 support for x86_64 and x86. All GCC
versions that can build glibc provide the required support, but since
GCC 6 and before don't provide __builtin_nanq / __builtin_nansq, sNaN
tests and some tests of NaN payloads need to be disabled with such
compilers (this does not affect the generated glibc binaries at all,
just the tests). bits/floatn.h declares float128 support to be
available for GCC versions that provide the required libgcc support
(4.3 for x86_64, 4.4 for i386 GNU/Linux, 4.5 for i386 GNU/Hurd);
compilation-only support was present some time before then, but not
really useful without the libgcc functions.
fenv_private.h needed updating to avoid trying to put _Float128 values
in registers. I make no assertion of optimality of the
math_opt_barrier / math_force_eval definitions for this case; they are
simply intended to be sufficient to work correctly.
Tested for x86_64 and x86, with GCC 7 and GCC 6. (Testing for x32 was
compilation tests only with build-many-glibcs.py to verify the ABI
baseline updates. I have not done any testing for Hurd, although the
float128 support is enabled there as for GNU/Linux.)
* sysdeps/i386/Implies: Add ieee754/float128.
* sysdeps/x86_64/Implies: Likewise.
* sysdeps/x86/bits/floatn.h: New file.
* sysdeps/x86/float128-abi.h: Likewise.
* manual/math.texi (Mathematics): Document support for _Float128
on x86_64 and x86.
* sysdeps/i386/fpu/fenv_private.h: Include <bits/floatn.h>.
(math_opt_barrier): Do not put _Float128 values in floating-point
registers.
(math_force_eval): Likewise.
[__x86_64__] (SET_RESTORE_ROUNDF128): New macro.
* sysdeps/x86/fpu/Makefile [$(subdir) = math] (CPPFLAGS): Append
to Makefile variable.
* sysdeps/x86/fpu/e_sqrtf128.c: New file.
* sysdeps/x86/fpu/sfp-machine.h: Likewise. Based on libgcc.
* sysdeps/x86/math-tests.h: New file.
* math/libm-test-support.h (XFAIL_FLOAT128_PAYLOAD): New macro.
* math/libm-test-getpayload.inc (getpayload_test_data): Use
XFAIL_FLOAT128_PAYLOAD.
* math/libm-test-setpayload.inc (setpayload_test_data): Likewise.
* math/libm-test-totalorder.inc (totalorder_test_data): Likewise.
* math/libm-test-totalordermag.inc (totalordermag_test_data):
Likewise.
* sysdeps/unix/sysv/linux/i386/libc.abilist: Update.
* sysdeps/unix/sysv/linux/i386/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Likewise.
* sysdeps/i386/fpu/libm-test-ulps: Likewise.
* sysdeps/i386/i686/fpu/multiarch/libm-test-ulps: Likewise.
* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
