Work around powerpc32 integer 0 converting to -0 (bug 887, bug 19049, bug 19050).
On powerpc32 hard-float, older processors (ones where fcfid is not
available for 32-bit code), GCC generates conversions from integers to
floating point that wrongly convert integer 0 to -0 instead of +0 in
FE_DOWNWARD mode. This in turn results in logb and a few other
functions wrongly returning -0 when they should return +0.
This patch works around this issue in glibc as I proposed in
<https://sourceware.org/ml/libc-alpha/2015-09/msg00728.html>, so that
the affected functions can be correct and the affected tests pass in
the absence of a GCC fix for this longstanding issue (GCC bug 67771 -
if fixed, of course we can put in GCC version conditionals, and
eventually phase out the workarounds). A new macro
FIX_INT_FP_CONVERT_ZERO is added in a new sysdeps header
fix-int-fp-convert-zero.h, and the powerpc32/fpu version of that
header defines the macro based on the results of a configure test for
whether such conversions use the fcfid instruction.
Tested for x86_64 (that installed stripped shared libraries are
unchanged by the patch) and powerpc (that HAVE_PPC_FCFID comes out to
0 as expected and that the relevant tests are fixed). Also tested a
build with GCC configured for -mcpu=power4 and verified that
HAVE_PPC_FCFID comes out to 1 in that case.
There are still some other issues to fix to get test-float and
test-double passing cleanly for older powerpc32 processors (apart from
the need for an ulps regeneration for powerpc). (test-ldouble will be
harder to get passing cleanly, but with a combination of selected
fixes to ldbl-128ibm code that don't involve significant performance
issues, allowing spurious underflow and inexact exceptions for that
format, and lots of XFAILing for the default case of unpatched libgcc,
it should be doable.)
[BZ #887]
[BZ #19049]
[BZ #19050]
* sysdeps/generic/fix-int-fp-convert-zero.h: New file.
* sysdeps/ieee754/dbl-64/e_log10.c: Include
<fix-int-fp-convert-zero.h>.
(__ieee754_log10): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/dbl-64/e_log2.c: Include
<fix-int-fp-convert-zero.h>.
(__ieee754_log2): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/dbl-64/s_erf.c: Include
<fix-int-fp-convert-zero.h>.
(__erfc): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/dbl-64/s_logb.c: Include
<fix-int-fp-convert-zero.h>.
(__logb): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/flt-32/e_log10f.c: Include
<fix-int-fp-convert-zero.h>.
(__ieee754_log10f): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/flt-32/e_log2f.c: Include
<fix-int-fp-convert-zero.h>.
(__ieee754_log2f): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/flt-32/s_erff.c: Include
<fix-int-fp-convert-zero.h>.
(__erfcf): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/flt-32/s_logbf.c: Include
<fix-int-fp-convert-zero.h>.
(__logbf): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/ldbl-128ibm/s_erfl.c: Include
<fix-int-fp-convert-zero.h>.
(__erfcl): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/ldbl-128ibm/s_logbl.c: Include
<fix-int-fp-convert-zero.h>.
(__logbl): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/powerpc/powerpc32/fpu/configure.ac: New file.
* sysdeps/powerpc/powerpc32/fpu/configure: New generated file.
* sysdeps/powerpc/powerpc32/fpu/fix-int-fp-convert-zero.h: New
file.
* config.h.in [_LIBC] (HAVE_PPC_FCFID): New macro.
2015-10-06 01:46:50 +08:00
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/* Fix for conversion of integer 0 to floating point. Generic version.
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2024-01-02 02:12:26 +08:00
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Copyright (C) 2015-2024 Free Software Foundation, Inc.
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Work around powerpc32 integer 0 converting to -0 (bug 887, bug 19049, bug 19050).
On powerpc32 hard-float, older processors (ones where fcfid is not
available for 32-bit code), GCC generates conversions from integers to
floating point that wrongly convert integer 0 to -0 instead of +0 in
FE_DOWNWARD mode. This in turn results in logb and a few other
functions wrongly returning -0 when they should return +0.
This patch works around this issue in glibc as I proposed in
<https://sourceware.org/ml/libc-alpha/2015-09/msg00728.html>, so that
the affected functions can be correct and the affected tests pass in
the absence of a GCC fix for this longstanding issue (GCC bug 67771 -
if fixed, of course we can put in GCC version conditionals, and
eventually phase out the workarounds). A new macro
FIX_INT_FP_CONVERT_ZERO is added in a new sysdeps header
fix-int-fp-convert-zero.h, and the powerpc32/fpu version of that
header defines the macro based on the results of a configure test for
whether such conversions use the fcfid instruction.
Tested for x86_64 (that installed stripped shared libraries are
unchanged by the patch) and powerpc (that HAVE_PPC_FCFID comes out to
0 as expected and that the relevant tests are fixed). Also tested a
build with GCC configured for -mcpu=power4 and verified that
HAVE_PPC_FCFID comes out to 1 in that case.
There are still some other issues to fix to get test-float and
test-double passing cleanly for older powerpc32 processors (apart from
the need for an ulps regeneration for powerpc). (test-ldouble will be
harder to get passing cleanly, but with a combination of selected
fixes to ldbl-128ibm code that don't involve significant performance
issues, allowing spurious underflow and inexact exceptions for that
format, and lots of XFAILing for the default case of unpatched libgcc,
it should be doable.)
[BZ #887]
[BZ #19049]
[BZ #19050]
* sysdeps/generic/fix-int-fp-convert-zero.h: New file.
* sysdeps/ieee754/dbl-64/e_log10.c: Include
<fix-int-fp-convert-zero.h>.
(__ieee754_log10): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/dbl-64/e_log2.c: Include
<fix-int-fp-convert-zero.h>.
(__ieee754_log2): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/dbl-64/s_erf.c: Include
<fix-int-fp-convert-zero.h>.
(__erfc): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/dbl-64/s_logb.c: Include
<fix-int-fp-convert-zero.h>.
(__logb): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/flt-32/e_log10f.c: Include
<fix-int-fp-convert-zero.h>.
(__ieee754_log10f): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/flt-32/e_log2f.c: Include
<fix-int-fp-convert-zero.h>.
(__ieee754_log2f): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/flt-32/s_erff.c: Include
<fix-int-fp-convert-zero.h>.
(__erfcf): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/flt-32/s_logbf.c: Include
<fix-int-fp-convert-zero.h>.
(__logbf): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/ldbl-128ibm/s_erfl.c: Include
<fix-int-fp-convert-zero.h>.
(__erfcl): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/ldbl-128ibm/s_logbl.c: Include
<fix-int-fp-convert-zero.h>.
(__logbl): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/powerpc/powerpc32/fpu/configure.ac: New file.
* sysdeps/powerpc/powerpc32/fpu/configure: New generated file.
* sysdeps/powerpc/powerpc32/fpu/fix-int-fp-convert-zero.h: New
file.
* config.h.in [_LIBC] (HAVE_PPC_FCFID): New macro.
2015-10-06 01:46:50 +08:00
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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Prefer https to http for gnu.org and fsf.org URLs
Also, change sources.redhat.com to sourceware.org.
This patch was automatically generated by running the following shell
script, which uses GNU sed, and which avoids modifying files imported
from upstream:
sed -ri '
s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g
s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g
' \
$(find $(git ls-files) -prune -type f \
! -name '*.po' \
! -name 'ChangeLog*' \
! -path COPYING ! -path COPYING.LIB \
! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \
! -path manual/texinfo.tex ! -path scripts/config.guess \
! -path scripts/config.sub ! -path scripts/install-sh \
! -path scripts/mkinstalldirs ! -path scripts/move-if-change \
! -path INSTALL ! -path locale/programs/charmap-kw.h \
! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \
! '(' -name configure \
-execdir test -f configure.ac -o -f configure.in ';' ')' \
! '(' -name preconfigure \
-execdir test -f preconfigure.ac ';' ')' \
-print)
and then by running 'make dist-prepare' to regenerate files built
from the altered files, and then executing the following to cleanup:
chmod a+x sysdeps/unix/sysv/linux/riscv/configure
# Omit irrelevant whitespace and comment-only changes,
# perhaps from a slightly-different Autoconf version.
git checkout -f \
sysdeps/csky/configure \
sysdeps/hppa/configure \
sysdeps/riscv/configure \
sysdeps/unix/sysv/linux/csky/configure
# Omit changes that caused a pre-commit check to fail like this:
# remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines
git checkout -f \
sysdeps/powerpc/powerpc64/ppc-mcount.S \
sysdeps/unix/sysv/linux/s390/s390-64/syscall.S
# Omit change that caused a pre-commit check to fail like this:
# remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline
git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
2019-09-07 13:40:42 +08:00
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<https://www.gnu.org/licenses/>. */
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Work around powerpc32 integer 0 converting to -0 (bug 887, bug 19049, bug 19050).
On powerpc32 hard-float, older processors (ones where fcfid is not
available for 32-bit code), GCC generates conversions from integers to
floating point that wrongly convert integer 0 to -0 instead of +0 in
FE_DOWNWARD mode. This in turn results in logb and a few other
functions wrongly returning -0 when they should return +0.
This patch works around this issue in glibc as I proposed in
<https://sourceware.org/ml/libc-alpha/2015-09/msg00728.html>, so that
the affected functions can be correct and the affected tests pass in
the absence of a GCC fix for this longstanding issue (GCC bug 67771 -
if fixed, of course we can put in GCC version conditionals, and
eventually phase out the workarounds). A new macro
FIX_INT_FP_CONVERT_ZERO is added in a new sysdeps header
fix-int-fp-convert-zero.h, and the powerpc32/fpu version of that
header defines the macro based on the results of a configure test for
whether such conversions use the fcfid instruction.
Tested for x86_64 (that installed stripped shared libraries are
unchanged by the patch) and powerpc (that HAVE_PPC_FCFID comes out to
0 as expected and that the relevant tests are fixed). Also tested a
build with GCC configured for -mcpu=power4 and verified that
HAVE_PPC_FCFID comes out to 1 in that case.
There are still some other issues to fix to get test-float and
test-double passing cleanly for older powerpc32 processors (apart from
the need for an ulps regeneration for powerpc). (test-ldouble will be
harder to get passing cleanly, but with a combination of selected
fixes to ldbl-128ibm code that don't involve significant performance
issues, allowing spurious underflow and inexact exceptions for that
format, and lots of XFAILing for the default case of unpatched libgcc,
it should be doable.)
[BZ #887]
[BZ #19049]
[BZ #19050]
* sysdeps/generic/fix-int-fp-convert-zero.h: New file.
* sysdeps/ieee754/dbl-64/e_log10.c: Include
<fix-int-fp-convert-zero.h>.
(__ieee754_log10): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/dbl-64/e_log2.c: Include
<fix-int-fp-convert-zero.h>.
(__ieee754_log2): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/dbl-64/s_erf.c: Include
<fix-int-fp-convert-zero.h>.
(__erfc): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/dbl-64/s_logb.c: Include
<fix-int-fp-convert-zero.h>.
(__logb): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/flt-32/e_log10f.c: Include
<fix-int-fp-convert-zero.h>.
(__ieee754_log10f): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/flt-32/e_log2f.c: Include
<fix-int-fp-convert-zero.h>.
(__ieee754_log2f): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/flt-32/s_erff.c: Include
<fix-int-fp-convert-zero.h>.
(__erfcf): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/flt-32/s_logbf.c: Include
<fix-int-fp-convert-zero.h>.
(__logbf): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/ldbl-128ibm/s_erfl.c: Include
<fix-int-fp-convert-zero.h>.
(__erfcl): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/ieee754/ldbl-128ibm/s_logbl.c: Include
<fix-int-fp-convert-zero.h>.
(__logbl): Adjust signs as needed if FIX_INT_FP_CONVERT_ZERO.
* sysdeps/powerpc/powerpc32/fpu/configure.ac: New file.
* sysdeps/powerpc/powerpc32/fpu/configure: New generated file.
* sysdeps/powerpc/powerpc32/fpu/fix-int-fp-convert-zero.h: New
file.
* config.h.in [_LIBC] (HAVE_PPC_FCFID): New macro.
2015-10-06 01:46:50 +08:00
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#ifndef FIX_INT_FP_CONVERT_ZERO_H
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#define FIX_INT_FP_CONVERT_ZERO_H 1
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/* Define this macro to 1 to work around conversions of integer 0 to
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floating point returning -0 instead of the correct +0 in some
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rounding modes. */
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#define FIX_INT_FP_CONVERT_ZERO 0
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#endif /* fix-int-fp-convert-zero.h */
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