[![Appveyor build status (Windows)](https://ci.appveyor.com/api/projects/status/xfllw9vkp3lj4l0v/branch/main?svg=true)](https://ci.appveyor.com/project/ispc/ispc/branch/main) [![Open in GitHub Codespaces](https://github.com/codespaces/badge.svg)](https://github.com/codespaces/new?hide_repo_select=true&ref=main&repo=1931356) # Intel® Implicit SPMD Program Compiler (Intel® ISPC) `ispc` is a compiler for a variant of the C programming language, with extensions for [single program, multiple data](http://en.wikipedia.org/wiki/SPMD) programming. Under the SPMD model, the programmer writes a program that generally appears to be a regular serial program, though the execution model is actually that a number of *program instances* execute in parallel on the hardware. ## Overview `ispc` compiles a C-based SPMD programming language to run on the SIMD units of CPUs and GPUs; it frequently provides a 3x or more speedup on architectures with 4-wide vector SSE units and 5x-6x on architectures with 8-wide AVX vector units, without any of the difficulty of writing intrinsics code. Parallelization across multiple cores is also supported by `ispc`, making it possible to write programs that achieve performance improvement that scales by both number of cores and vector unit size. There are a few key principles in the design of `ispc`: * To build a small set of extensions to the C language that would deliver excellent performance to performance-oriented programmers who want to run SPMD programs on the CPU and GPU. * To provide a thin abstraction layer between the programmer and the hardware--in particular, to have an execution and data model where the programmer can cleanly reason about the mapping of their source program to compiled assembly language and the underlying hardware. * To make it possible to harness the computational power of SIMD vector units without the extremely low-programmer-productivity activity of directly writing intrinsics. * To explore opportunities from close coupling between C/C++ application code and SPMD `ispc` code running on the same processor--to have lightweight function calls between the two languages and to share data directly via pointers without copying or reformatting. `ispc` is an open source compiler with the BSD license. It uses the remarkable [LLVM Compiler Infrastructure](http://llvm.org) for back-end code generation and optimization and is [hosted on github](http://github.com/ispc/ispc). It supports Windows, macOS, and Linux as a host operating system and also capable to target Android, iOS, and PS4/PS5. It currently supports multiple flavours of x86 (SSE2, SSE4, AVX, AVX2, and AVX512), ARM (NEON), and Intel® GPU architectures (Gen9 and Xe family). ## Features `ispc` provides a number of key features to developers: * Familiarity as an extension of the C programming language: `ispc` supports familiar C syntax and programming idioms, while adding the ability to write SPMD programs. * High-quality SIMD code generation: the performance of code generated by `ispc` is often close to that of hand-written intrinsics code. * Ease of adoption with existing software systems: functions written in `ispc` directly interoperate with application functions written in C/C++ and with application data structures. * Portability across over a decade of CPU generations: `ispc` has targets for x86 SSE2, SSE4, AVX, AVX2, and AVX512, as well as ARM NEON and recent Intel® GPUs. * Portability across operating systems: Microsoft Windows, macOS, Linux, and FreeBSD are all supported by `ispc`. * Debugging with standard tools: `ispc` programs can be debugged with standard debuggers. ## Installation ### Official Release Binaries You can download the official release binaries from [the latest release page](https://github.com/ispc/ispc/releases/latest). Choose the appropriate version for your operating system and architecture. ### Linux (Snap Store) Linux users can install `ispc` using the Snap Store: ```bash snap install ispc ``` ### Intel® oneAPI Distribution `ispc` is distributed as part of the Intel® oneAPI. You can install it from the corresponding repositories for DEB-based and RPM-based Linux distributions. Follow the instructions below: DEB-based Linux (Ubuntu, Debian, etc.) First, download the key to the system keyring: ```bash wget -O- https://apt.repos.intel.com/intel-gpg-keys/GPG-PUB-KEY-INTEL-SW-PRODUCTS.PUB | gpg --dearmor | sudo tee /usr/share/keyrings/oneapi-archive-keyring.gpg > /dev/null ``` Next, add the signed entry to apt sources and configure the APT client to use the Intel repository: ```bash echo "deb [signed-by=/usr/share/keyrings/oneapi-archive-keyring.gpg] https://apt.repos.intel.com/oneapi all main" | sudo tee /etc/apt/sources.list.d/oneAPI.list ``` Update the package list and install `ispc`: ```bash sudo apt-get update sudo apt-get install intel-oneapi-ispc ``` The installation location is inside the `/opt/intel/` directory. To use `ispc`, either use the full path `/opt/intel/oneapi/ispc/latest/bin/ispc` or add the `bin` directory to your `PATH`: ```bash source /opt/intel/oneapi/ispc/latest/env/vars.sh ``` ### Other Package Managers Thanks to community support, `ispc` is also available through a variety of package managers on multiple operating systems. ### Windows To install `ispc` on Windows, you can download the latest release as `zip` archive from [the latest release page](https://github.com/ispc/ispc/releases/latest). Then you need to unpack that to some directory. It is user's responsibility to set-up permissions for this directory according to the principle of least privilege. Moreover, `ispc` depends on run-time components of Visual C++ (DLLs). These libraries can be installed with Microsoft Visual C++ Redistributable package. Instruction to install them can be found [here](https://learn.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist). ## Additional Resources Latest `ispc` binaries corresponding to `main` branch can be downloaded from Appveyor for [Linux](https://ci.appveyor.com/api/projects/ispc/ispc/artifacts/build%2Fispc-trunk-linux.tar.gz?job=Environment%3A%20APPVEYOR_BUILD_WORKER_IMAGE%3DUbuntu1804%2C%20LLVM_VERSION%3Dlatest) and [Windows](https://ci.appveyor.com/api/projects/ispc/ispc/artifacts/build%2Fispc-trunk-windows.zip?job=Environment%3A%20APPVEYOR_BUILD_WORKER_IMAGE%3DVisual%20Studio%202019%2C%20LLVM_VERSION%3Dlatest) See also additional [documentation](https://ispc.github.io/documentation.html) and additional [performance information](https://ispc.github.io/perf.html). If you have a bug report and have a question, you are welcome to open an [issue](https://github.com/ispc/ispc/issues) or start a [discussion](https://github.com/ispc/ispc/discussions) on GitHub.