This patch adds the narrowing fused multiply-add functions from TS
18661-1 / TS 18661-3 / C2X to glibc's libm: ffma, ffmal, dfmal,
f32fmaf64, f32fmaf32x, f32xfmaf64 for all configurations; f32fmaf64x,
f32fmaf128, f64fmaf64x, f64fmaf128, f32xfmaf64x, f32xfmaf128,
f64xfmaf128 for configurations with _Float64x and _Float128;
__f32fmaieee128 and __f64fmaieee128 aliases in the powerpc64le case
(for calls to ffmal and dfmal when long double is IEEE binary128).
Corresponding tgmath.h macro support is also added.
The changes are mostly similar to those for the other narrowing
functions previously added, especially that for sqrt, so the
description of those generally applies to this patch as well. As with
sqrt, I reused the same test inputs in auto-libm-test-in as for
non-narrowing fma rather than adding extra or separate inputs for
narrowing fma. The tests in libm-test-narrow-fma.inc also follow
those for non-narrowing fma.
The non-narrowing fma has a known bug (bug 6801) that it does not set
errno on errors (overflow, underflow, Inf * 0, Inf - Inf). Rather
than fixing this or having narrowing fma check for errors when
non-narrowing does not (complicating the cases when narrowing fma can
otherwise be an alias for a non-narrowing function), this patch does
not attempt to check for errors from narrowing fma and set errno; the
CHECK_NARROW_FMA macro is still present, but as a placeholder that
does nothing, and this missing errno setting is considered to be
covered by the existing bug rather than needing a separate open bug.
missing-errno annotations are duly added to many of the
auto-libm-test-in test inputs for fma.
This completes adding all the new functions from TS 18661-1 to glibc,
so will be followed by corresponding stdc-predef.h changes to define
__STDC_IEC_60559_BFP__ and __STDC_IEC_60559_COMPLEX__, as the support
for TS 18661-1 will be at a similar level to that for C standard
floating-point facilities up to C11 (pragmas not implemented, but
library functions done). (There are still further changes to be done
to implement changes to the types of fromfp functions from N2548.)
Tested as followed: natively with the full glibc testsuite for x86_64
(GCC 11, 7, 6) and x86 (GCC 11); with build-many-glibcs.py with GCC
11, 7 and 6; cross testing of math/ tests for powerpc64le, powerpc32
hard float, mips64 (all three ABIs, both hard and soft float). The
different GCC versions are to cover the different cases in tgmath.h
and tgmath.h tests properly (GCC 6 has _Float* only as typedefs in
glibc headers, GCC 7 has proper _Float* support, GCC 8 adds
__builtin_tgmath).
include/math.h has a mechanism to redirect internal calls to various
libm functions, that can often be inlined by the compiler, to call
non-exported __* names for those functions in the case when the calls
aren't inlined, with the redirection being disabled when
NO_MATH_REDIRECT. Add fma to the functions to which this mechanism is
applied.
At present, libm-internal fma calls (generally to __builtin_fma*
functions) are only done when it's known the call will be inlined,
with alternative code not relying on an fma operation being used in
the caller otherwise. This patch is in preparation for adding the TS
18661 / C2X narrowing fma functions to glibc; it will be natural for
the narrowing function implementations to call the underlying fma
functions unconditionally, with this either being inlined or resulting
in an __fma* call. (Using two levels of round-to-odd computation like
that, in the case where there isn't an fma hardware instruction, isn't
optimal but is certainly a lot simpler for the initial implementation
than writing different narrowing fma implementations for all the
various pairs of formats.)
Tested with build-many-glibcs.py that installed stripped shared
libraries are unchanged by the patch (using
<https://sourceware.org/pipermail/libc-alpha/2021-September/130991.html>
to fix installed library stripping in build-many-glibcs.py). Also
tested for x86_64.
We stopped adding "Contributed by" or similar lines in sources in 2012
in favour of git logs and keeping the Contributors section of the
glibc manual up to date. Removing these lines makes the license
header a bit more consistent across files and also removes the
possibility of error in attribution when license blocks or files are
copied across since the contributed-by lines don't actually reflect
reality in those cases.
Move all "Contributed by" and similar lines (Written by, Test by,
etc.) into a new file CONTRIBUTED-BY to retain record of these
contributions. These contributors are also mentioned in
manual/contrib.texi, so we just maintain this additional record as a
courtesy to the earlier developers.
The following scripts were used to filter a list of files to edit in
place and to clean up the CONTRIBUTED-BY file respectively. These
were not added to the glibc sources because they're not expected to be
of any use in future given that this is a one time task:
https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dchttps://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
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 converts libm function implementations in math/ from using
weak_alias to using libm_alias_double to define public function names,
in cases where it would be appropriate to define _Float64 / _Float32x
aliases for those functions as well. This eliminates many
NO_LONG_DOUBLE conditionals and ldbl-opt wrappers round these function
implementations.
Tested for x86_64. Also tested with build-many-glibcs.py. Binary
differences seen are that the different order in which remainder and
drem symbols get defined as a result of this patch (the same source
file defines the same aliases, but in a different order of definition)
changes the order of symbols in the final libm.so when long double =
double, and for ldbl-opt configurations, the compat symbols for Bessel
functions were previously defined by e.g. "compat_symbol (libm, j0,
j0l, GLIBC_2_0)", which declares j0l as a compat symbol based on j0
and so makes j0l weak because j0 is weak, and are now defined
(indirectly via the relevant macros) based on e.g. __j0, so are no
longer weak because __j0 isn't weak.
* math/s_fma.c: Include <libm-alias-double.h>.
(fma): Define using libm_alias_double.
* math/s_nextafter.c: Include <libm-alias-double.h>.
(nextafter): Define using libm_alias_double.
* math/w_acos_compat.c: Include <libm-alias-double.h>.
(acos): Define using libm_alias_double.
* math/w_acosh_compat.c: Include <libm-alias-double.h>.
(aocsh): Define using libm_alias_double.
* math/w_asin_compat.c: Include <libm-alias-double.h>.
(asin): Define using libm_alias_double.
* math/w_atan2_compat.c: Include <libm-alias-double.h>.
(atan2): Define using libm_alias_double.
* math/w_atanh_compat.c: Include <libm-alias-double.h>.
(atanh): Define using libm_alias_double.
* math/w_cosh_compat.c: Include <libm-alias-double.h>.
(cosh): Define using libm_alias_double.
* math/w_exp10_compat.c: Include <libm-alias-double.h>.
(exp10): Define using libm_alias_double.
* math/w_exp2_compat.c: Include <libm-alias-double.h>.
(exp2): Define using libm_alias_double.
* math/w_exp_compat.c: Include <libm-alias-double.h>.
(exp): Define using libm_alias_double.
* math/w_fmod_compat.c: Include <libm-alias-double.h>.
(fmod): Define using libm_alias_double.
* math/w_hypot_compat.c: Include <libm-alias-double.h>.
(hypot): Define using libm_alias_double.
* math/w_j0_compat.c: Include <libm-alias-double.h>.
(j0): Define using libm_alias_double.
(y0): Likewise.
* math/w_j1_compat.c: Include <libm-alias-double.h>.
(j1): Define using libm_alias_double.
(y1): Likewise.
* math/w_jn_compat.c: Include <libm-alias-double.h>.
(jn): Define using libm_alias_double.
(yn): Likewise.
* math/w_log10_compat.c: Include <libm-alias-double.h>.
(log10): Define using libm_alias_double.
* math/w_log2_compat.c: Include <libm-alias-double.h>.
(log2): Define using libm_alias_double.
* math/w_log_compat.c: Include <libm-alias-double.h>.
(log): Define using libm_alias_double.
* math/w_pow_compat.c: Include <libm-alias-double.h>.
(pow): Define using libm_alias_double.
* math/w_remainder_compat.c: Include <libm-alias-double.h>.
(remainder): Define using libm_alias_double.
* math/w_sinh_compat.c: Include <libm-alias-double.h>.
(sinh): Define using libm_alias_double.
* math/w_sqrt_compat.c: Include <libm-alias-double.h>.
(sqrt): Define using libm_alias_double.
* math/w_tgamma_compat.c: Include <libm-alias-double.h>.
(tgamma): Define using libm_alias_double.
* sysdeps/ieee754/ldbl-opt/s_nextafter.c [LONG_DOUBLE_COMPAT(libm,
GLIBC_2_0)] (nextafterl): Do not define compat symbol here.
* sysdeps/ieee754/ldbl-opt/w_exp10_compat.c
[LONG_DOUBLE_COMPAT(libm, GLIBC_2_1)] (exp10l): Likewise.
* sysdeps/ieee754/ldbl-opt/w_remainder_compat.c
[LONG_DOUBLE_COMPAT(libm, GLIBC_2_0)] (remainderl): Likewise.
* sysdeps/ieee754/ldbl-opt/w_acos_compat.c: Remove.
* sysdeps/ieee754/ldbl-opt/w_acosh_compat.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_asin_compat.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_atan2_compat.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_atanh_compat.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_cosh_compat.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_exp_compat.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_fmod_compat.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_hypot_compat.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_j0_compat.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_j1_compat.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_jn_compat.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_log10_compat.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_log2_compat.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_log_compat.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_pow_compat.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_sinh_compat.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_sqrt_compat.c: Likewise.
* sysdeps/ieee754/ldbl-opt/w_tgamma_compat.c: Likewise.
