Use expm1f(x) = exp(x) - 1 for |x| > ln(2).
For |x| <= ln(2), divide it into 3 subintervals: [-ln2, -1/8], [-1/8, 1/8], [1/8, ln2]
and use a degree-6 polynomial approximation generated by Sollya's fpminmax for each interval.
Errors < 1.5 ULPs when we use fma to evaluate the polynomials.
Differential Revision: https://reviews.llvm.org/D101134
The implementations use the x86_64 FPU instructions. These instructions
are extremely slow compared to a polynomial based software
implementation. Also, their accuracy falls drastically once the input
goes beyond 2PI. To improve both the speed and accuracy, we will be
taking the following approach going forward:
1. As a follow up to this CL, we will implement a range reduction algorithm
which will expand the accuracy to the entire double precision range.
2. After that, we will replace the HW instructions with a polynomial
implementation to improve the run time.
After step 2, the implementations will be accurate, performant and target
architecture independent.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D102384
Current implementation defines LIBC_TARGET_MACHINE with the use of CMAKE_SYSTEM_PROCESSOR.
Unfortunately CMAKE_SYSTEM_PROCESSOR is OS dependent and can produce different results.
An evidence of this is the various matchers used to detect whether the architecture is x86.
This patch normalizes LIBC_TARGET_MACHINE and renames it LIBC_TARGET_ARCHITECTURE.
I've added many architectures but we may want to limit ourselves to x86 and ARM.
Differential Revision: https://reviews.llvm.org/D101524
The current generic implementation of the fmaf function has been moved
to the FPUtil directory. This allows one use the fma operation from
implementations of other math functions like the trignometric functions
without depending on/requiring the fma/fmaf/fmal function targets. If
this pattern ends being convenient, we will switch all generic math
implementations to this pattern.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D100811
This helps us avoid the uncomfortable reinterpret-casts. Avoiding the
reinterpret casts prevents us from tripping the sanitizers as well.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D100360
This change also introduces a new source layout for adding machine
specific and generic implementations. To keep the scope of this change
small, this new pattern is only applied for ceil, ceilf and ceill.
Follow up changes will switch all math functions in to the new pattern.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D95850
this will make sure that all of the functions are using the correct
prototypes. Explained much better in the comments of this diff:
https://reviews.llvm.org/D94195
Summary:
The new macro also inserts the C alias for the C++ implementations
without needing an objcopy based post processing step. The CMake
rules have been updated to reflect this. More CMake cleanup can be
taken up in future rounds and appropriate TODOs have been added for them.
Reviewers: mcgrathr, sivachandra
Subscribers:
A differential fuzzer for these functions has also been added.
Along the way, a small correction has been done to the normal/subnormal
limits of x86 long double values.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D94109
The implementation is exactly the same as rint* as even rint does not
raise any floating point exceptions currently. [Note that the standards
do not specify that floating point exceptions must be raised - they
leave it up to the implementation to choose to raise FE_INEXACT when
rounding non-integral values.]
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D94112
A new function to MPFRWrapper has been added, which is used to set up
the unit tests.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D93007
Refactor src/math/hypotf.cpp and test/src/math/hypotf_test.cpp and reuse them for hypot and hypot_test
Differential Revision: https://reviews.llvm.org/D91831
This switches all of the files in src/string, src/math, and
test/src/math from using relative paths (e.g. `#include “include/string.h”`)
to global paths (e.g. `#include <string.h>`) to make bringing up those
functions on other platforms, such as fuchsia, easier.
Reviewed By: sivachandra
Differential Revision: https://reviews.llvm.org/D91394
The rounding behavior of NormalFloat to float format has been changed
to round to nearest. Also, a bug in NormalFloat to subnormal number
conversion has been fixed.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D91591
The implementation is not fully standards compliant in the sense that
errno is not set on error, and floating point exceptions are not raised.
Subnormal range and normal range are tested separately in the tests.
Reviewed By: lntue
Differential Revision: https://reviews.llvm.org/D86666
Current implementations of single precision and double precision
floating point operations operate on bits of the integer type of
same size. The code made use of magic masks which were listed as
literal integer values. This is not possible in the case of long
double type as the mantissa of quad-precision long double type used
on non-x86 architectures is wider that the widest integer type for
which we can list literal values. So, in this patch, to avoid
using magic masks specified with literal values, we use packed
bit-field struct types and let the compiler generate the masks.
This new scheme allows us to implement long double flavors of the
various floating point operations. To keep the size of the patch
small, only the implementations of fabs and trunc have been
switched to the new scheme. In following patches, all exisiting
implementations will be switched to the new scheme.
Reviewers: asteinhauser
Differential Revision: https://reviews.llvm.org/D82036
Implementations of copysign[f], frexp[f], logb[f], and modf[f] are added.
Reviewers: asteinhauser
Differential Revision: https://reviews.llvm.org/D81134
NFC intended in the implementaton. Only mechanical changes to fit the LLVM
libc implementation standard have been done.
Math testing infrastructure has been added. This infrastructure compares the
results produced by the libc with the high precision results from MPFR.
Tests making use of this infrastructure have been added for cosf, sinf and
sincosf.
Reviewers: abrachet, phosek
Differential Revision: https://reviews.llvm.org/D76825
Summary:
Made all header files consistent based of this documentation: https://llvm.org/docs/CodingStandards.html#file-headers.
And did the same for all source files top of file comments.
Reviewers: sivachandra, abrachet
Reviewed By: sivachandra, abrachet
Subscribers: MaskRay, tschuett, libc-commits
Tags: #libc-project
Differential Revision: https://reviews.llvm.org/D77533
Setup demonstrated in this patch is only for ELF-ish platforms.
Also note:
1. Use of redirectors is a temporary scheme. They will be removed once
LLVM-libc has implementations for the redirected functions.
2. Redirectors are optional. One can choose to not include them in the
LLVM-libc build for their platform.
3. Even with redirectors used, we want to link to the system libc
dynamically.
Reviewers: dlj, hfinkel, jakehehrlich, phosek, stanshebs, theraven, alexshap
Subscribers: mgorny, libc-commits
Tags: #libc-project
Differential Revision: https://reviews.llvm.org/D69020
Siva Chandra Reddy