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llvm / llvm-project / 8dc89e34199b6b1d0f5ea1f9940ccc8e957eef0a
commit8dc89e34199b6b1d0f5ea1f9940ccc8e957eef0a[log] [tgz]
authorPaul Walker <paul.walker@arm.com>Wed Apr 30 13:21:46 2025 +0100
committerGitHub <noreply@github.com>Wed Apr 30 13:21:46 2025 +0100
treeed14e31288af369a6fb045ef7eb9d8ad55740a12
parent5b6fc610919cc2e88fe3d9bfcc23637c75a636c9 [diff]
[LLVM][InstCombine] Enable constant folding for SVE asr,lsl and lsr intrinsics. (#137350)

The SVE intrinsics support shift amounts greater-than-or-equal to the
element type's bit-length, essentially saturating the shift amount to
the bit-length. However, the IR instructions consider this undefined
behaviour that results in poison. To account for this we now ignore the
result of the simplifications that result in poison. This allows
existing code to be used to simplify the shifts but does mean:

1) We don't simplify cases like "svlsl_s32(x, splat(32)) => 0".
2) We no longer constant fold cases like "svadd(poison, X) => poison"

For (1) we'd need dedicated target specific combines anyway and the
result of (2) is not specified by the ACLE and replicating LLVM IR
behaviour might be confusing to ACLE writers.
3 files changed
tree: ed14e31288af369a6fb045ef7eb9d8ad55740a12
  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

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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.