[MemDep] Optimize SortNonLocalDepInfoCache sorting strategy for large caches with few unsorted entries (#143107)

During compilation of large files with many branches, I observed that
the function `SortNonLocalDepInfoCache` in `MemoryDependenceAnalysis`
becomes a significant performance bottleneck. This is because
`Cache.size()` can be very large (around 20,000), but only a small
number of entries (approximately 5 to 8) actually need sorting. The
original implementation performs a full sort in all cases, which is
inefficient.

This patch introduces a lightweight heuristic to quickly estimate the
number of unsorted entries and choose a more efficient sorting method
accordingly.

As a result, the GVN pass runtime on a large file is reduced from
approximately 26.3 minutes to 16.5 minutes.
1 file changed
tree: 31b9455d60c01bb02f387b8a288359386cf6e50f
  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. runtimes/
  25. third-party/
  26. utils/
  27. .clang-format
  28. .clang-format-ignore
  29. .clang-tidy
  30. .git-blame-ignore-revs
  31. .gitattributes
  32. .gitignore
  33. .mailmap
  34. CODE_OF_CONDUCT.md
  35. CONTRIBUTING.md
  36. LICENSE.TXT
  37. pyproject.toml
  38. README.md
  39. SECURITY.md
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