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llvm / llvm-project / 4829dedfa9bb3d1e15aaa88cf1ff329c7b0e59de
commit4829dedfa9bb3d1e15aaa88cf1ff329c7b0e59de[log] [tgz]
authorAmara Emerson <amara@apple.com>Wed Sep 03 10:25:52 2025 -0700
committerGitHub <noreply@github.com>Wed Sep 03 10:25:52 2025 -0700
treecc2cf3cca5e9c5181b94b279e9d1878c371d6bf0
parent714f6b03bc89bff766ae628092cd059fd8aa0aa1 [diff]
[GlobalISel] Add multi-way splitting support for wide scalar shifts. (#155353)

This patch implements direct N-way splitting for wide scalar shifts
instead
of recursive binary splitting. For example, an i512 G_SHL can now be
split
directly into 8 i64 operations rather than going through i256 -> i128 ->
i64.

The main motivation behind this is to alleviate (although not entirely
fix)
pathological compile time issues with huge types, like i4224. The
problem
we see is that the recursive splitting strategy combined with our messy
artifact combiner ends up with terribly long compiles as tons of
intermediate
artifacts are generated, and then attempted to be combined ad-nauseum.

Going directly from the large shifts to the destination types
short-circuits
a lot of these issues, but it's still an abuse of the backend and
front-ends
should never be doing this sort of thing.
4 files changed
tree: cc2cf3cca5e9c5181b94b279e9d1878c371d6bf0
  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. libsycl/
  16. libunwind/
  17. lld/
  18. lldb/
  19. llvm/
  20. llvm-libgcc/
  21. mlir/
  22. offload/
  23. openmp/
  24. orc-rt/
  25. polly/
  26. runtimes/
  27. third-party/
  28. utils/
  29. .clang-format
  30. .clang-format-ignore
  31. .clang-tidy
  32. .git-blame-ignore-revs
  33. .gitattributes
  34. .gitignore
  35. .mailmap
  36. CODE_OF_CONDUCT.md
  37. CONTRIBUTING.md
  38. LICENSE.TXT
  39. pyproject.toml
  40. README.md
  41. SECURITY.md
README.md

The LLVM Compiler Infrastructure

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Welcome to the LLVM project!

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