mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2025-04-07 16:42:07 +00:00
7e67a4b0cb
Some early revisions of the Cortex-A53 have an erratum (835769) whereby it is possible for a 64-bit multiply-accumulate instruction in AArch64 state to generate an incorrect result. The details are quite complex and hard to determine statically, since branches in the code may exist in some circumstances, but all cases end with a memory (load, store, or prefetch) instruction followed immediately by the multiply-accumulate operation. The safest work-around for this issue is to make the compiler avoid emitting multiply-accumulate instructions immediately after memory instructions and the simplest way to do this is to insert a NOP. This patch implements such work-around in the backend, enabled via the option -aarch64-fix-cortex-a53-835769. The work-around code generation is not enabled by default. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219603 91177308-0d34-0410-b5e6-96231b3b80d8
Low Level Virtual Machine (LLVM) ================================ This directory and its subdirectories contain source code for the Low Level Virtual Machine, 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.