# VC Intrinsics ## Introduction VC Intrinsics project contains a set of new intrinsics on top of core LLVM IR instructions that represent SIMD semantics of a program targeting GPU. This set is now used by * CMC - https://github.com/intel/cm-compiler * DPC++ - https://github.com/intel/llvm * ISPC - https://github.com/ispc/ispc frontend compilers and * IGC VC backend - https://github.com/intel/intel-graphics-compiler ## License VC Intrinsics are distributed under the MIT license. You may obtain a copy of the License at: https://opensource.org/licenses/MIT ## Dependencies ### Source code * LLVM Project - https://github.com/llvm/llvm-project ### Tools To build libraries: * CMake - https://cmake.org/ - 3.13.4 or later * Python - https://www.python.org/ - 2.7 or later * C++ compiler - anything that can compile LLVM To build documentation: * Sphinx - https://www.sphinx-doc.org - 1.5 or later * GNU Make - https://www.gnu.org/software/make/ - 3.79 or later * Standard Unix utilities (mkdir, rm, sed) ## Building VC Intrinsics can be built in two major modes: in-tree and external. All major LLVM versions starting from LLVM 8 are supported. LLVM ToT can be used too, but there is no guarantee that it will always work (because of sudden breaking changes in LLVM C++ API). However, maintainers are trying to fix such issues as fast as possible. ### In-tree build For in-tree build VC Intrinsics can be considered as an external LLVM project. Put VC Intrinsics source directory inside `llvm/projects` directory or add `-DLLVM_EXTERNAL_PROJECTS="vc-intrinsics" -DLLVM_EXTERNAL_VC_INTRINSICS_SOURCE_DIR=` to cmake command arguments when configuring LLVM. ### External build To configure VC Intrinsics with prebuilt LLVM run cmake as follows: ```shell $ cmake -DLLVM_DIR=/lib/cmake/llvm ``` ### Documentation VC Intrinsics documentation is inside `docs` subdirectory and can be built using Sphinx. To build html version do the following: ```shell $ cd docs $ make -f Makefile.sphinx html ``` This will extract comments from main intrinsics description and generate readable html output in `_build/html` subdirectory. ## Testing VC Intrinsics repository contains lit tests that are enabled when `-DVC_INTR_ENABLE_LIT_TESTS=ON` is passed to cmake command. Lit tests use LLVM plugins and currently are supported only with dynamic LLVM (when LLVM is configured with `-DLLVM_LINK_LLVM_DYLIB=ON`). In external build path to `lit` utility should be specified as follows: `-DLLVM_EXTERNAL_LIT=`. Full example with external build: ```shell $ cmake -DLLVM_DIR=/lib/cmake/llvm -DVC_INTR_ENABLE_LIT_TESTS=ON -DLLVM_EXTERNAL_LIT= ``` Target `check-vc-intrinsics` will run lit tests. ## How to provide feedback Please submit an issue using native github.com interface: https://github.com/intel/vc-intrinsics/issues. ## How to contribute Create a pull request on github.com with your patch. A maintainer will contact you if there are questions or concerns.