Both IEEE-754 2008 and ISO/IEC TS 18661-4 define the half-cycle
trignometric functions cospi, sinpi, and tanpi. The attached
patch implements cospi[fl], sinpi[fl], and tanpi[fl]. Limited
testing on the cospi and sinpi reveal a max ULP less than 0.89;
while tanpi is more problematic with a max ULP less than 2.01
in the interval [0,0.5]. The algorithms used in these functions
are documented in {ks}_cospi.c, {ks}_sinpi.c, and s_tanpi.c.
Note. I no longer have access to a system with ld128 and
adequate support to compile and test the ld128 implementations
of these functions. Given the almost complete lack of input from
others on improvements to libm, I doubt that anyone cares. If
someone does care, the ld128 files contain a number of FIXME comments,
and in particular, while the polynomial coefficients are given
I did not update the polynomial algorithms to properly use the
coefficients.
PR: 218514
MFC after: 2 weeks
These files were copied from MUSL. Add the standard copyright notice and
SPDX-License-Identifier: MIT consistent with our new draft license
policy. It reads word for word the same as the MIT license on the SPDX
web site. Add a pointer to the MUSL COPYIRGHT file which contains a list
of all authors of MUSL.
Sponsored by: Netflix
Noticed by: Steve Kargl
Summary:
From Steve Kargl:
Paul Zimmermann has identified a bug in Openlibm's powf(),
which is identical to FreeBSD's libm. Both derived from
fdlibm. https://github.com/JuliaMath/openlibm/issues/212.
Consider
% cat h.c
int
main(void)
{
float x, y, z;
x = 0x1.ffffecp-1F;
y = -0x1.000002p+27F;
z = 0x1.557a86p115F;
printf("%e %e %e <-- should be %e\n", x, y, powf(x,y), z);
return 0;
}
% cc -o h -fno-builtin h.c -lm && ./h
9.999994e-01 -1.342177e+08 inf <-- should be 5.540807e+34
Reviewers: manu
Subscribers: imp, andrew, emaste
Differential Revision: https://reviews.freebsd.org/D31865
.Fa is the suitable macro for functions in comparsion to the
.Ar macro, which should be used for commandline arguments.
While here, fix some mandoc warnings.
Reviewed by: imp (earlier version)
Obtained from: OpenBSD (in partial)
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D31090
After df3b437c1e, older gcc's such as
4.2.1 (still used on earlier branches for e.g. mips and powerpc) and
6.3.0 (still used for some cross-builds) started throwing bogus errors
like:
In file included from /workspace/src/lib/msun/src/s_llround.c:11:0:
/workspace/src/lib/msun/src/s_lround.c:54:31: error: initializer element is not constant
static const type dtype_min = type_min - 0.5;
^~~~~~~~
/workspace/src/lib/msun/src/s_lround.c:55:31: error: initializer element is not constant
static const type dtype_max = type_max + 0.5;
^~~~~~~~
Since 'type_min' and 'type_max' are constants declared just above these
lines this error is nonsensical, but older gcc's are not smart enough.
Work around the error by reusing the (type)DTYPE_MIN and (type)DTYPE_MAX
macros, so I can MFC this right away, unbreaking a few stable builds.
MFC after: immediately
It turned out that the (type)DTYPE_MAX conversions at the top of
s_lround.c are now emitted as cvtsi2sd instructions, at least on SSE
capable CPUs. This caused the FE_INEXACT flag to always be set, at least
for the double and float variants. Under clang 11, the whole INRANGE()
comparisons were still optimized away, but this has "improved" in clang
12, due to stricter adherence to the -ffp-exception-behavior=maytrap
compiler flag.
To avoid run-time integer to float conversions, use static constants
instead, so they are computed at compile time, and the INRANGE()
statements are optimized away again, if applicable.
While here, use an integer instead of a floating type to store the test
results in lround_test.c, as this is more appropriate, and we can also
drop the volatile hack.
Reported by: arichardson
MFC after: 3 days
Summary:
Fix FPU exception management for powerpcspe. Bits are in a different place from
the standard FPSCR, so we need to handle the shifting differences. Also,
there's no concept of a "software exception" raise, so we need to do exceptional
math to trigger the exception from software.
Reviewed By: alfredo
Differential Revision: https://reviews.freebsd.org/D22824
For some reason the ld128 log1pl() implementation is less accurate than
logl(), but does at least guarantee precision >= the ld80 implementation.
Mark log1p_accuracy_tests as XFAIL for ld128 and increase the log1p tolerance
to the ld80 equivalent in accuracy_tests to avoid losing test coverage for
the other functions.
PR: 253984
Reviewed By: ngie, dim
Differential Revision: https://reviews.freebsd.org/D29039
This avoids build failures due to the clang 12 warning:
'#pragma FENV_ACCESS' is not supported on this target - ignored
Clang 12 currently emits this warning for all non-x86 architectures.
While this can result in incorrect code generation (e.g. on AArch64 some
exceptions are not raised as expected), this is a pre-existing issue and
we should not fail the build due to this warning.
Reviewed By: dim, emaste
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D29743
After 3b00222f15, it turns out that clang only supports strict
floating point semantics for SystemZ and x86 at the moment, while for
other architectures it is still experimental.
Therefore, only use -fp-exception-behavior=maytrap on x86 for now,
otherwise this option results in "error: overriding currently
unsupported use of floating point exceptions on this target
[-Werror,-Wunsupported-floating-point-opt]" on other architectures.
Fixes: 3b00222f15
PR: 254911
MFC after: 1 week
When using clang with x86_64 CPUs that support AVX, some floating point
transformations may raise exceptions that would not have been raised by
the original code. To avoid this, use the -fp-exception-behavior=maytrap
flag, introduced in clang 10.0.0.
In particular, this fixes a number of test failures with ctanhf(3) and
ctanf(3), when libm is compiled with -mavx. An unexpected FE_INVALID
exception is then raised, because clang emits vdivps instructions to
perform certain divides. (The vdivps instruction operates on multiple
single-precision float operands simultaneously, but the exceptions may
be influenced by unused parts of the XMM registers. In this particular
case, it was calculating 0 / 0, which results in FE_INVALID.)
If -fp-exception-behavior=maytrap is specified however, clang uses
vdivss instructions instead, which work on one operand, and should not
raise unexpected exceptions.
Reported by: olivier
Reviewed by: arichardson
PR: 254911
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D29686
When compiling parts of math.h with clang using a C standard before C11,
and using -pedantic, it will result in warnings similar to:
bug254714.c:5:11: warning: '_Generic' is a C11 extension [-Wc11-extensions]
return !isfinite(1.0);
^
/usr/include/math.h:111:21: note: expanded from macro 'isfinite'
^
/usr/include/math.h:82:39: note: expanded from macro '__fp_type_select'
^
This is because the block that enables use of _Generic is conditional
not only on C11, but also on whether the compiler advertises support for
C generic selections via __has_extension(c_generic_selections).
To work around the warning without having to pessimize the code, use the
__extension__ keyword, which is supported by both clang and gcc. While
here, remove the check for __clang__, as _Generic has been supported for
a long time by gcc too now.
Reported by: yuri
PR: 254714
MFC after: 1 week
The man page says "The feenableexcept(), fedisableexcept(), and
fegetexcept() functions return a bitmap of the exceptions that were
unmasked prior to the call.", so we should return zero not -1.
Reviewed By: mhorne
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D29386
After increasing the lib/msun/tests WARNS to 6, this triggers a
compilation error for RISC-V.
Fixes: 87d65c747a ("lib/msun: Allow building tests with WARNS=6")
Reported by: Jenkins
The LLVM bug was fixed a long time ago and with D29076 this test actually
passes now.
Reviewed By: andrew
Differential Revision: https://reviews.freebsd.org/D29092
If long double has more than 64 mantissa bits, using uint64_t to hold the
mantissa bits will truncate the value and result in test failures. To fix
this problem use __uint128_t since all platforms that have
__LDBL_MANT_DIG__ > 64 also have compiler support for 128-bit integers.
Reviewed By: rlibby
Differential Revision: https://reviews.freebsd.org/D29076
I only tested the WARNS=6 change on AArch64 and AMD64, but this file has
unused functions for architectures with LDBL_PREC == 53.
While touching this file change the LDBL_PREC == 53 checks to i386 checks.
The long double tests should only be disabled for i386 (due to the rather
odd rounding mode that it uses) not all architectures where long double
is the same as double.
PR: 205449
Fixes: 87d65c747a ("lib/msun: Allow building tests with WARNS=6")
Reported by: Jenkins
Some CPUs (e.g. AArch64 QEMU) cannot trap on floating point exceptions and
therefore ignore the writes to the floating point control register inside
feenableexcept(). If no exceptions are enabled after
feenableexcept(FE_ALL_EXCEPT), we can assume that the CPU does not
support exceptions and we can then skip the test.
Reviewed By: dim
Differential Revision: https://reviews.freebsd.org/D29095
These appears to have been resolved by compiling the test with -fno-builtin
and/or using a newer compiler.
PR: 208703
Reviewed By: ngie
Differential Revision: https://reviews.freebsd.org/D28884
This provides better error messages that just an assertion failure and
also makes it easier to mark individual tests as XFAIL.
It was also helpful when coming up with D28786 and D28787.
Differential Revision: https://reviews.freebsd.org/D28798
Apparently GCC only supports arithmetic expressions that use static
const variables in initializers starting with GCC8. To keep older
versions happy use a macro instead.
Fixes: 221622ec0c ("lib/msun: Avoid FE_INEXACT for x86 log2l/log10l")
Reported by: Jenkins
Reviewed By: imp
Differential Revision: https://reviews.freebsd.org/D29233
The existing code masked off all bits that it didn't know about. To be
future-proof, we should save and restore the entire fpcr/fpsr registers.
Additionally, the existing fesetenv() was incorrectly setting the rounding
mode in fpsr instead of fpcr.
This patch stores fpcr in the high 32 bits of fenv_t and fpsr in the low
bits instead of trying to interleave them in a single 32-bit field.
Technically, this is an ABI break if you re-compile parts of your code or
pass a fenv_t between DSOs that were compiled with different versions
of fenv.h. However, I believe we should fix this since the existing code
was broken and passing fenv_t across DSOs should rarely happen.
Reviewed By: andrew
Differential Revision: https://reviews.freebsd.org/D29160
This fixes tests/lib/msun/logarithm_test after compiling the test with
-fno-builtin (D28577). Adding invln10_lo + invln10_10 results in
FE_INEXACT (for all inputs) and the same for the log2l invln2_lo + invln2_hi.
This patch avoids FE_INEXACT (for exact results such as 0) by defining a
constant and using that.
Reviewed By: dim
Differential Revision: https://reviews.freebsd.org/D28786
This caused LDBL_MANT_DIG to not be defined and therefore the scalbnl
alias was not being emitted for double==long double platforms.
Fixes: 760b2ffc ("Update scalbn* functions to the musl versions")
Reported by: Jenkins
The only diff compared to musl is a minor change to scalbnl() to replace
musl's union ldshape with union IEEEl2bits.
This fixes the scalbn tests on non-x86 (since x86 has an assembly version
that is used instead).
Musl commit messages:
commit 8c44a060243f04283ca68dad199aab90336141db
Author: Szabolcs Nagy <nsz@port70.net>
Date: Mon Apr 3 02:38:13 2017 +0200
fix scalbn when result is in the subnormal range
in nearest rounding mode scalbn could introduce double rounding error
when an intermediate value and the final result were both in the
subnormal range e.g.
scalbn(0x1.7ffffffffffffp-1, -1073)
returned 0x1p-1073 instead of 0x1p-1074, because the intermediate
computation got rounded to 0x1.8p-1023.
with the fix an intermediate value can only be in the subnormal range
if the final result is 0 which is correct even after double rounding.
(there still can be two roundings so signals may be raised twice, but
that's only observable with trapping exceptions which is not supported.)
commit 2eaed464e2080d8321d3903b71086a1ecfc4ee4a
Author: Szabolcs Nagy <nsz@port70.net>
Date: Wed Sep 4 15:52:54 2013 +0000
math: use float_t and double_t in scalbnf and scalbn
remove STRICT_ASSIGN (c99 semantics is assumed) and use the conventional
union to prepare the scaling factor (so libm.h is no longer needed)
commit 1b77b9072f374bd26eb0574b83a0d5f18d75ec60
Author: Szabolcs Nagy <nsz@port70.net>
Date: Thu Aug 15 10:07:46 2013 +0000
math: minor scalbn*.c simplification
commit c4359e01303da2755fe7e8033826b132eb3659b1
Author: Szabolcs Nagy <nsz@port70.net>
Date: Tue Nov 13 10:55:35 2012 +0100
math: excess precision fix modf, modff, scalbn, scalbnf
old code was correct only if the result was stored (without the
excess precision) or musl was compiled with -ffloat-store.
now we use STRICT_ASSIGN to work around the issue.
(see note 160 in c11 section 6.8.6.4)
commit 666271c105e4137bdfa195e217799d74143370d4
Author: Szabolcs Nagy <nsz@port70.net>
Date: Tue Nov 13 10:30:40 2012 +0100
math: fix scalbn and scalbnf on overflow/underflow
old code was correct only if the result was stored (without the
excess precision) or musl was compiled with -ffloat-store.
(see note 160 in n1570.pdf section 6.8.6.4)
commit 8051e08e10d2b739fcfcbc6bc7466e8d77fa49f1
Author: nsz <nsz@port70.net>
Date: Mon Mar 19 10:54:07 2012 +0100
simplify scalbn*.c implementations
The old scalbn.c was wrong and slow, the new one is just slow.
(scalbn(0x1p+1023,-2097) should give 0x1p-1074, but the old code gave 0)
Reviewed By: dim
Differential Revision: https://reviews.freebsd.org/D28872
This forces the compiler to emit calls to libm functions, instead of
possibly substituting pre-calculated results at compile time, which
should help to actually test those functions.
Reviewed by: emaste, arichardson, ngie
Differential Revision: https://reviews.freebsd.org/D28577
MFC after: 3 days
I did this without a full vendor update since that would cause too many
conflicts. Since these files now almost match the NetBSD sources the
next git subtree merge should work just fine.
Reviewed By: lwhsu
Differential Revision: https://reviews.freebsd.org/D28797
This applies musl commit b02eed9c4841913d690a2d0029737d72615384fe by
Szabolcs Nagy and updates the tests accordingly. This also allows
removing an XFAIL from the test.
musl commit message:
complex: fix ctanh(+-0+i*nan) and ctanh(+-0+-i*inf)
These cases were incorrect in C11 as described by
http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1886.htm
PR: 217528
Reviewed By: dim
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D28578
This adjusts the factor used to scale the subnormal numbers, so it
becomes the right value after adjusting its exponent. Thanks to Steve
Kargl for finding the most elegant fix.
Also enable the hypot tests, and add a test case for this bug.
PR: 253313
MFC after: 1 week
This sprinkles a few strategic volatiles in an attempt to defeat clang's
optimization interfering with the expected floating-point exception
flags.
Reported by: lwhsu
PR: 244732
MFC after: 3 days
This tests fork()s, so if there is still data in the stdout buffer on fork
it will print it again in the child process. This was happening in the
CheriBSD CI and caused the test to complain about malformed TAP output.
Reviewed By: ngie
Differential Revision: https://reviews.freebsd.org/D28397
SVN r343917 fixed this for in-tree clang, but when building with a newer
out-of-tree clang the test was still marked as XFAIL.
Reviewed By: dim
Differential Revision: https://reviews.freebsd.org/D28390
Follow-up to r353959 and r368070: do the same for other architectures.
arm32 already seems to use its own .fnstart/.fnend directives, which
appear to be ARM-specific variants of the same thing. Likewise, MIPS
uses .frame directives.
Reviewed by: arichardson
Differential Revision: https://reviews.freebsd.org/D27387
Some platforms have additional architecture-specific floating-point flags.
Msun test cases lrint and test_fegsetenv (fenv) expects only standard flags,
so make sure to mask them appropriately.
This makes test pass on PowerPC64.
Reviewed by: jhibbits, ngie
Sponsored by: Eldorado Research Institute (eldorado.org.br)
Differential Revision: https://reviews.freebsd.org/D27202
Fix incorrect mask being used when FE_INVALID bit is wanted by user.
The problem was noticed thanks to msun fenv tests.
Reviewed by: jhibbits, luporl
Sponsored by: Eldorado Research Institute (eldorado.org.br)
Differential Revision: https://reviews.freebsd.org/D27201
The intel compiler support has badly decayed over the years. Stop
pretending that we support it. Note, I've stopped short of requiring
gcc builtin support with this commit since other compilers may be used
to build non-base software and we need to support those so more
investigation is needed before simplifying further.
by Steve Kargl:
- Use sincos[f] instead of a call to cos[f] and a call to sin[f].
- While here, alphabetize declaration.
Submitted by: sgk at troutmask.apl.washington.edu (Steve Kargl)
- Micro-optimization: use sincosl(x) instead of a call to cosl(x) and
a call to sinl(x). Argument reduction is done once not twice.
- Use a long double constant instead of an invalid double constant.
- Spell scale2 correctly
He could not test ld128, so that patch is untested.
Submitted by: sgk at troutmask.apl.washington.edu (Steve Kargl)
Some of the NetBSD contributed tests are gated behind the
__HAVE_LONG_DOUBLE flag. This flag seems to be defined only for
platforms whose long double is larger than their double. I could not
find this explicitly documented anywhere, but it is implied by the
definitions in NetBSD's sys/arch/${arch}/include/math.h headers, and the
following assertion from the UBSAN code:
#ifdef __HAVE_LONG_DOUBLE
long double LD;
ASSERT(sizeof(LD) > sizeof(uint64_t));
#endif
RISC-V has 128-bit long doubles, so enable the tests on this platform,
and update the comments to better explain the purpose of this flag.
Reviewed by: ngie
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D25419
Assume gcc is at least 6.4, the oldest xtoolchain in the ports tree.
Assume clang is at least 6, which was in 11.2-RELEASE. Drop conditions
for older compilers.
Reviewed by: imp (earlier version), emaste, jhb
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D24802
These functions first appeared in the First Edition of Unix (or earlier in the
pdp-7 version). Just claim 1st Edition for all this. The pdp-7 code is too
fragmented at this point to extend history that far back.
The "for" loop on big endian was inverting all the bits instead of
just the words
Issue reported by TestSuite (msun lib nan_test case)
Submitted by: Renato Riolino <renato.riolino@eldorado.org.br>
Submitted by: Fernando Valle <fernando.valle@eldorado.org.br>
Reviewed by: pfg, alfredo
Approved by: jhibbits (mentor)
Sponsored by: Eldorado Research Institute (eldorado.org.br)
Differential Revision: https://reviews.freebsd.org/D23926
Once upon a time, sparc64 was the only ld128 architecture. However,
both aarch64 and riscv are now such architectures. Many of the
comments about how slow multiplication was on old sparc64 processors
are now no longer true. However, since no evaluation has been done for
aarch64 yet, it's unclear if they are still relevant or not. If not,
the code should be changed. If so, the comments should remove the
uncertainty.
Reviewed by: emaste@
Differential Revision: https://reviews.freebsd.org/D23658
environ(7) was in AT&T Version 7
ac(8): Add a HISTORY section
sa(8): Add a HISTORY section
sqrt(3): Add the actual sqrt function to the HISTORY section
Obtained from: OpenBSD
Submitted by: gbergling@gmail.com
Approved by: bcr@(mentor)
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D23693
In r355656, endianness handling of the floating point environment was fixed
in the PowerPC code to work as intended.
However, one bit got missed, causing feholdexcept() to mis-save the fenv.
Submitted by: Renato Riolino <renato.riolino@eldorado.org.br>
Differential Revision: https://reviews.freebsd.org/D23382
Per the University California Regents letter, drop the so-called
"advertisement" clause.
Discussed with: bde, kargl (2017)
Differential Revision: https://reviews.freebsd.org/D22928
Fix multiple problems in the powerpcspe floating point code.
* Endianness handling of the SPEFSCR in fenv.h was completely broken.
* Ensure SPEFSCR synchronization requirements are being met.
The __r.__d -> __r transformations were written by jhibbits.
Reviewed by: jhibbits
Differential Revision: https://reviews.freebsd.org/D22526
Update a bunch of Makefile.depend files as
a result of adding Makefile.depend.options files
Reviewed by: bdrewery
MFC after: 1 week
Sponsored by: Juniper Networks
Differential Revision: https://reviews.freebsd.org/D22494
negative numbers (invoking undefined behavior)
Summary:
Various paths through hypot(x, y) will multiply x and y by a power of
two, perform the calculation in a range where IEEE-754 provides greater
precision, then undo the multiplication to determine the true result.
Undoing that multiplication is implemented as t1*w, where t1=2**k.
2**k is often computed by taking the high word of 1.0, then adding k<<20
(for doubles or long doubles) or k<<23 (for floats) to it, then
overwriting that high word. But when k is negative this left-shifts a
negative value -- and that's undefined behavior in many editions of C
and C++.
This patch should fix all hypot implementations to compute 2**k without
triggering this particular bit of undefined behavior.
Test Plan: I've only very lightly tested out the hypot(double, double)
change, in SpiderMonkey's JavaScript engine, for consistency with prior
behavior. The other functions' changes have more or less only been
eyeballed. Careful examination appreciated! Do note, however, that an
error in any of these changes would most likely produce a value that is
incorrect by a factor of two, so any mistake would most likely be
glaring if invoked.
Submitted by: Jeff Walden <jwalden@mit.edu>
Obtained from: https://github.com/freebsd/freebsd/pull/414
Reviewed by: dim, lwhsu
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D22354
Alter bsd.compat.mk to set MACHINE and MACHINE_ARCH when included
directly so MD paths in Makefiles work. In the process centralize
setting them in LIBCOMPATWMAKEENV.
Alter .PATH and CFLAGS settings in work when the Makefile is included.
While here only support LIB32 on supported platforms rather than always
enabling it and requiring users of MK_LIB32 to filter based
TARGET/MACHINE_ARCH.
The net effect of this change is to make Makefile.libcompat only build
compatability libraries.
Changes relative to r354449:
Correct detection of the compiler type when bsd.compat.mk is used
outside Makefile.libcompat. Previously it always matched the clang
case.
Set LDFLAGS including the linker emulation for mips where -m32 seems to
be insufficent.
Reviewed by: imp, kib (origional version in r354449)
Obtained from: CheriBSD (conceptually)
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D22251
Even though clang comes with a number of internal CUDA wrapper headers,
compiling sample CUDA programs will result in errors similar to:
In file included from <built-in>:1:
In file included from /usr/lib/clang/9.0.0/include/__clang_cuda_runtime_wrapper.h:204:
/usr/home/arr/cuda/var/cuda-repo-10-0-local-10.0.130-410.48/usr/local/cuda-10.0//include/crt/math_functions.hpp:2910:7: error: no matching function for call to '__isnan'
if (__isnan(a)) {
^~~~~~~
/usr/lib/clang/9.0.0/include/__clang_cuda_device_functions.h:460:16: note: candidate function not viable: call to __device__ function from __host__ function
__DEVICE__ int __isnan(double __a) { return __nv_isnand(__a); }
^
CUDA expects __isnan() and __isnanf() declarations to be available,
which are glibc specific extensions, equivalent to the regular isnan()
and isnanf().
To provide these, define __isnan() and __isnanf() as aliases of the
already existing static inline functions __inline_isnan() and
__inline_isnanf() from math.h.
Reported by: arrowd
PR: 241550
MFC after: 1 week
Clang from trunk recently added a warning for when implicit int-to-float
conversions cause a loss of precision. The code in question is designed
to be able to handle that, so add explicit casts to silence this.
Submitted by: James Clarke <jrtc27@jrtc27.com>
Reviewed by: dim
Obtained from: CheriBSD
MFC after: 1 week
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D21913
C/C++) in exp(3), expf(3), expm1(3) and expm1f(3) during intermediate
computations that compute the IEEE-754 bit pattern for |2**k| for
integer |k|.
The implementations of exp(3), expf(3), expm1(3) and expm1f(3) need to
compute IEEE-754 bit patterns for 2**k in certain places. (k is an
integer and 2**k is exactly representable in IEEE-754.)
Currently they do things like 0x3FF0'0000+(k<<20), which is to say they
take the bit pattern representing 1 and then add directly to the
exponent field to get the desired power of two. This is fine when k is
non-negative.
But when k<0 (and certain classes of input trigger this), this
left-shifts a negative number -- an operation with undefined behavior in
C and C++.
The desired semantics can be achieved by instead adding the
possibly-negative k to the IEEE-754 exponent bias to get the desired
exponent field, _then_ shifting that into its proper overall position.
(Note that in case of s_expm1.c and s_expm1f.c, there are SET_HIGH_WORD
and SET_FLOAT_WORD uses further down in each of these files that perform
shift operations involving k, but by these points k's range has been
restricted to 2 < k <= 56, and the shift operations under those
circumstances can't do anything that would be UB.)
Submitted by: Jeff Walden, https://github.com/jswalden
Obtained from: https://github.com/freebsd/freebsd/pull/411
Obtained from: https://github.com/freebsd/freebsd/pull/412
MFC after: 3 days
This unskips:
- lib.libc.stdlib.strtod_test.strtod_round
- lib.msun.fe_round_test.t_nofe_round
In lib/msun/tests/Makefile only define on fe_round_test.c because
lib.msun.ilogb_test.ilogb will get wrong results and needs more examination.
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
This makes it possible to perform mathematical operations on
fractional values without using floating point. It operates on Q
numbers, which are integer-sized, opaque structures initialized
to hold a chosen number of integer and fractional bits.
For a general description of the Q number system, see the "Fixed Point
Representation & Fractional Math" whitepaper[1]; for the actual
API see the qmath(3) man page.
This is one of dependencies for the upcoming stats(3) framework[2]
that will be applied to the TCP stack in a later commit.
1. https://www.superkits.net/whitepapers/Fixed%20Point%20Representation%20&%20Fractional%20Math.pdf
2. https://reviews.freebsd.org/D20477
Reviewed by: bcr (man pages, earlier version), sef (earlier version)
Discussed with: cem, dteske, imp, lstewart
Sponsored By: Klara Inc, Netflix
Obtained from: Netflix
Differential Revision: https://reviews.freebsd.org/D20116
Ensure the expected result is stored first in a volatile variable with
the desired type. This makes all the tests succeed.
Slightly changed from the original pull request, but functionally the
same.
Obtained from: https://github.com/freebsd/freebsd/pull/401
Submitted by: Moritz Buhl <gh@moritzbuhl.de>
PR: 191676
MFC after: 3 days
Replace calls to sinf(x) and cosf(x) with a single call to sincosf().
Submitted by: Steve Kargl <sgk@troutmask.apl.washington.edu>
Reviewed by: bde
Approved by: grog
MFC after: 3 days
trig_test.reduction test cases to fail, if the fixes from r343916 have
not yet been applied to the base compiler.
Reported by: lwhsu
PR: 234040
Upstream PR: https://bugs.llvm.org/show_bug.cgi?id=40206
MFC after: 1 week
j is int32_t and thus j<<31 is undefined if j==1.
Hinted by: muusl-lib (git 688d3da0f1730daddbc954bbc2d27cc96ceee04c)
Discussed with: freebsd-numerics (kargl)
The long double aliases of double functions are only exposed as aliases if
LDBL_MANT_DIG is 53 (same as DBL_MANT_DIG). Without float.h included these
files were not exposing weak aliases as expected, leading to link failures
if programs use the *l functions. This should fix editors/calligra on
targets with 64-bit long double, which uses erfl and erfcl. Found on
powerpc64.
Reviewed by: kargl@
of NaNs before possible returning a NaN.
The remquo*() and remainder*() functions should now give bitwise identical
results across arches and implementations, and bitwise consistent results
(with lower precisions having truncated mantissas) across precisions. x86
already had consistency across amd64 and i386 and precisions by using the
i387 consistently and normally not using the C versions. Inconsistencies
for C reqmquol() were first detected on sparc64.
Remove double second clearing of the sign bit and extra blank lines.
remainder*(x, y) and remquo*(x, y, quo) were broken for y = 0 by changing
multiplication by y to addition of y. (When y is 0, the result should be
NaN but became 1 for finite x.)
Use a new macro nan_mix_op() to give more control over the mixing, and
expand comments.
Recent re-testing missed finding this bug since I only tested the macro
version on amd64 and i386 and these arches don't use the C versions (they
use either asm versions or builtins).
Reported by: enh via freebsd-numerics
This is a follow-up to r336299.
* lib/msun/Makefile:
. Remove polevll.c
* lib/msun/ld80/e_powl.c:
. Copy contents of polevll.c to here. This is the only consumer of
these functions. Make functions 'static inline'.
. Make reducl a 'static inline' function.
* lib/msun/man/exp.3:
. Remove BUGS section that no longer applies.
* lib/msun/src/math_private.h:
. Remove prototypes of __p1evll() and __polevll()
* lib/msun/src/s_cpow.c:
* lib/msun/src/s_cpowf.c:
* lib/msun/src/s_cpowl.c
. Include math_private.h.
. Use the CMPLX macro from either C99 or math_private.h (depends on
compiler support) instead of the problematic use of complex I.
Submitted by: Steve Kargl <sgk@troutmask.apl.washington.edu>
PR: 229876
MFC after: 1 week
This was open-coded in range reduction for trig and exp functions. Now
there are 3 static inline functions rnint[fl]() that replace open-coded
expressions, and type-generic irint() and i64rint() macros that hide the
complications for efficiently using non-generic irint() and irintl()
functions and casts.
Special details:
ld128/e_rem_pio2l.h needs to use i64rint() since it needs a 46-bit integer
result. Everything else only needs a (less than) 32-bit integer result so
uses irint().
Float and double cases now use float_t and double_t locally instead of
STRICT_ASSIGN() to avoid bugs in extra precision.
On amd64, inline asm is now only used for irint() on long doubles. The SSE
asm for irint() on amd64 only existed because the ifdef tangles made the
correct method of simply casting to int for this case non-obvious.
cc1: warnings being treated as errors
/usr/src/lib/msun/src/s_cpow.c: In function 'cpow':
/usr/src/lib/msun/src/s_cpow.c:63: warning: implicit declaration of function 'CMPLX'
This is a follow-up to r336299.
* lib/msun/Makefile:
. Remove polevll.c
* lib/msun/ld80/e_powl.c:
. Copy contents of polevll.c to here. This is the only consumer of
these functions. Make functions 'static inline'.
. Make reducl a 'static inline' function.
* lib/msun/man/exp.3:
. Remove BUGS section that no longer applies.
* lib/msun/src/math_private.h:
. Remove prototypes of __p1evll() and __polevll()
* lib/msun/src/s_cpow.c:
* lib/msun/src/s_cpowf.c:
* lib/msun/src/s_cpowl.c
. Use the CMPLX macro from either C99 or math_private.h (depends of
compiler support) instead of the problematic use of complex I.
Submitted by: Steve Kargl <sgk@troutmask.apl.washington.edu>
PR: 229876
MFC after: 1 week
with 1 huge component and 1 tiny (but nowhere near denormal) component.
Rescale earlier so that a scale factor of 2 can be combined with a non-
scale divisor of 2, so that the division doesn't shift out a bit. In the
usual case where the scale factor is just 1, the division may shift out a
bit, but then the underflow is not spurious and the inaccuracies are harder
to fix.
Remove the STDC CX_LIMITED_RANGE pragma and its verbose comment. We still
don't have any C99 compilers (that support fenv pragmas), and if we did
then there are thousands of other places in libm that would need to use
them more than here.
The other cleanups are smaller.
and csqrtl().
When one component is huge and the other is tiny, scaling down the tiny
component gave spurious underflow.
When both components are denormal, not scaling them up gave inaccuracies
of 34+ ulps on not very carefully selected args. Fixing this reduces the
maximum error to 1.6 ulps on the same set of args (mosly not denormal ones).
The scaling used multiplication of a complex variable by 2, but clang messes
this on amd64 up by losing the sign of -0.0. Calculate the components
separately, as is well known to be needed for operations on more exceptional
values.
independent of the precision in most cases. This is mainly to simplify
checking for errors. r176266 did this for e_pow[f].c using a less
refined expression that often didn't work. r176276 fixes an error in
the log message for r176266. The main refinement is to always expand
to long double precision. See old log messages (especially these 2)
and the comment on the macro for more general details.
Specific details:
- using nan_mix() consistently for the new and old pow*() functions was
the only thing needed to make my consistency test for powl() vs pow()
pass on amd64.
- catrig[fl].c already had all the refinements, but open-coded.
- e_atan2[fl].c, e_fmod[fl].c and s_remquo[fl] only had primitive NaN
mixing.
- e_hypot[fl].c already had a different refined version of r176266. Refine
this further. nan_mix() is not directly usable here since we want to
clear the sign bit.
- e_remainder[f].c already had an earlier version of r176266.
- s_ccosh[f].c,/s_csinh[f].c already had a version equivalent to r176266.
Refine this further. nan_mix() is not directly usable here since the
expression has to handle some non-NaN cases.
- s_csqrt.[fl]: the mixing was special and mostly wrong. Partially fix the
special version.
- s_ctanh[f].c already had a version of r176266.
This corresponds to the latest status (hasn't changed in 9+
years) from openbsd of ld80/ld128 powl, and source cpowf, cpow,
cpowl (the complex power functions for float complex, double
complex, and long double complex) which are required for C99
compliance and were missing from FreeBSD. Also required for
some numerical codes using complex numbered Hamiltonians.
Thanks to jhb for tracking down the issue with making
weak_reference compile on powerpc.
When asked to review, bde said "I don't like it" - but
provided no actionable feedback or superior implementations.
Discussed with: jhb
Submitted by: jmd
Differential Revision: https://reviews.freebsd.org/D15919
Remove unnecessary casts, use integer literal constants instead of
floating point constants where possible, and introduce three const
static variables to hold 0.5, 0.25, and 1/3.
PR: 229420
Submitted by: Steve Kargl <sgk@troutmask.apl.washington.edu>
MFC after: 1 week