The idea is to move all pieces related to the actual libc sources to the "src" directory. This allows downstream users to ship and build just the "src" directory. Reviewed By: michaelrj Differential Revision: https://reviews.llvm.org/D112653
These functions will be used in a future patch to implement trigonometric functions. Unit tests have been added but to the libc-long-running-tests suite. The unit tests long running because we compare against MPFR computations performed at 1280 bits of precision. Some cleanups or elimination of repeated patterns can be done as follow up changes. Differential Revision: https://reviews.llvm.org/D104817
Some ctype functions are called from other libc functions (e.g. isspace is used in atoi). By moving ctype_utils.h to __support it becomes easier to include just the implementations of these functions. For these reasons the implementation for isspace was moved into ctype_utils as well. FPUtils was moved to simplify the build order, and to clarify which files are a part of the actual libc. Many files were modified to accomodate these changes, mostly changing the #include paths. Reviewed By: sivachandra Differential Revision: https://reviews.llvm.org/D107600
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
Fixes Aarch64 bot.
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