[AArch64] Re-enable rematerialization for streaming-mode-changing functions. (#83235) We can add implicit defs/uses of the 'VG' register to the instructions to prevent the register allocator from rematerializing values in between streaming-mode changes, as the def/use of VG will further nail down the ordering that comes out of ISel. This avoids the heavy-handed approach to prevent any kind of rematerialization. While we could add 'VG' as a Use to all SVE instructions, we only really need to do this for instructions that are rematerializable, as the smstart/smstop instructions and pseudos act as scheduling barriers which is sufficient to prevent other instructions from being scheduled in between the streaming-mode-changing call sequence. However, we may revisit this in the future.
Welcome to the LLVM project!
This repository contains the source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and run-time environments.
The LLVM project has multiple components. The core of the project is itself called “LLVM”. This contains all of the tools, libraries, and header files needed to process intermediate representations and convert them into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer.
C-like languages use the Clang frontend. This component compiles C, C++, Objective-C, and Objective-C++ code into LLVM bitcode -- and from there into object files, using LLVM.
Other components include: the libc++ C++ standard library, the LLD linker, and more.
Consult the Getting Started with LLVM page for information on building and running LLVM.
For information on how to contribute to the LLVM project, please take a look at the Contributing to LLVM guide.
Join the LLVM Discourse forums, Discord chat, LLVM Office Hours or Regular sync-ups.
The LLVM project has adopted a code of conduct for participants to all modes of communication within the project.