Google Git
Sign in
llvm / llvm-project / 1c722fc8f5671ab1bbb7965b3b5fbba0645884b0
commit1c722fc8f5671ab1bbb7965b3b5fbba0645884b0[log] [tgz]
authorPhilip Reames <preames@rivosinc.com>Tue Apr 22 10:50:20 2025 -0700
committerGitHub <noreply@github.com>Tue Apr 22 10:50:20 2025 -0700
treeed6505ba7f619be202186f2b3a719b98d2e9b72d
parent55678dcbd5e4a4e096a2c856ac2f5dbfa57acc00 [diff]
[RISCV][TTI] Use processShuffleMask for shuffle legalization estimate (#136191)

We had some code which tried to estimate legalization costs for
illegally typed shuffles, but it only handled the case of a widening
shuffle, and used a somewhat adhoc heuristic. We can reuse the
processShuffleMask utility (which we already use for individual vector
register splitting when exact VLEN is known) to perform the same
splitting given the legal vector type as the unit of split instead. This
makes the costing both simpler and more robust.

Note that this swings costs for illegal shuffles pretty wildly as we
were previously sometimes hitting the adhoc code, and sometimes falling
through into generic scalarization costing. I don't know that any of the
costs for the individual tests in tree are significant, but the test
which which triggered me finding this was reported to me by Alexey
reduced from something triggering a bad choice in SLP for x264. So this
has the potential to be somewhat high impact.
4 files changed
tree: ed6505ba7f619be202186f2b3a719b98d2e9b72d
  1. .ci/
  2. .github/
  3. bolt/
  4. clang/
  5. clang-tools-extra/
  6. cmake/
  7. compiler-rt/
  8. cross-project-tests/
  9. flang/
  10. flang-rt/
  11. libc/
  12. libclc/
  13. libcxx/
  14. libcxxabi/
  15. libunwind/
  16. lld/
  17. lldb/
  18. llvm/
  19. llvm-libgcc/
  20. mlir/
  21. offload/
  22. openmp/
  23. polly/
  24. pstl/
  25. runtimes/
  26. third-party/
  27. utils/
  28. .clang-format
  29. .clang-format-ignore
  30. .clang-tidy
  31. .git-blame-ignore-revs
  32. .gitattributes
  33. .gitignore
  34. .mailmap
  35. CODE_OF_CONDUCT.md
  36. CONTRIBUTING.md
  37. LICENSE.TXT
  38. pyproject.toml
  39. README.md
  40. SECURITY.md
README.md

The LLVM Compiler Infrastructure

OpenSSF Scorecard OpenSSF Best Practices libc++

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.

Getting the Source Code and Building LLVM

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.

Getting in touch

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.