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llvm / llvm-project / 96ab74bf175f46de4b6fbfc68deecd3567e42a52
commit96ab74bf175f46de4b6fbfc68deecd3567e42a52[log] [tgz]
authorJameson Nash <vtjnash@gmail.com>Fri Jun 20 10:32:31 2025 -0400
committerGitHub <noreply@github.com>Fri Jun 20 10:32:31 2025 -0400
tree3e383401220c8c62c56bf071090cee1380a7aff9
parentf242360e156b407902829d694c036b2d22211894 [diff]
[InstCombine] remove undef loads, such as memcpy from undef (#143958)

Extend `isAllocSiteRemovable` to be able to check if the ModRef info
indicates the alloca is only Ref or only Mod, and be able to remove it
accordingly. It seemed that there were a surprising number of
benchmarks with this pattern which weren't getting optimized previously
(due to MemorySSA walk limits). There were somewhat more existing tests
than I'd like to have modified which were simply doing exactly this
pattern (and thus relying on undef memory). Claude code contributed the
new tests (and found an important typo that I'd made).

This implements the discussion in
https://github.com/llvm/llvm-project/pull/143782#discussion_r2142720376.
14 files changed
tree: 3e383401220c8c62c56bf071090cee1380a7aff9
  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.

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