mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2025-02-14 02:33:53 +00:00
2c5f9584ba
The IBM BG/Q supercomputer's A2 cores have a hardware prefetching unit, the L1P, but it does not prefetch directly into the A2's L1 cache. Instead, it prefetches into its own L1P buffer, and the latency to access that buffer is significantly higher than that to the L1 cache (although smaller than the latency to the L2 cache). As a result, especially when multiple hardware threads are not actively busy, explicitly prefetching data into the L1 cache is advantageous. I've been using this pass out-of-tree for data prefetching on the BG/Q for well over a year, and it has worked quite well. It is enabled by default only for the BG/Q, but can be enabled for other cores as well via a command-line option. Eventually, we might want to add some TTI interfaces and move this into Transforms/Scalar (there is nothing particularly target dependent about it, although only machines like the BG/Q will benefit from its simplistic strategy). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229966 91177308-0d34-0410-b5e6-96231b3b80d8
Low Level Virtual Machine (LLVM) ================================ This directory and its subdirectories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments. LLVM is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt. Please see the documentation provided in docs/ for further assistance with LLVM, and in particular docs/GettingStarted.rst for getting started with LLVM and docs/README.txt for an overview of LLVM's documentation setup. If you're writing a package for LLVM, see docs/Packaging.rst for our suggestions.