[RISCV] Adjust RISCVVectorMaskDAGMutation to look for copy to V0 (#129296) This mutation was introduced in 01a15dca0 with the goal of avoiding many copies from V1-v31 to v0 immediately before a mask consuming instruction. I noticed in a workload that this was not applying to vmv.s.x (which we use for short vector masks). We'd had a whitelist of instructions. Instead, we can directly inspect the user of the current node to see if it's a copy to V0. This isn't quite precise (as the mask producing instruction could already be scheduled fairly far from it's single use), but is probably good enough. As with all schedule changes, results are mixed. Some significant improvements, some regressions.
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.