[GlobalMerge] Add MinSize feature to the GlobalMerge Pass. (#93686)

We add a feature that prevents the GlobalMerge pass from considering
data smaller than a minimum size in bytes for merging.

The MinSize is set in 3 ways:
1. If global-merge-min-data-size is explicitly set, then it uses that
value.
2. If SmallDataLimit is set and non-zero, then SmallDataLimit + 1 is
used.
3. Otherwise, 0 is used, which means all sizes are considered for
merging.

We found that this feature allowed us to see the benefit of the
GlobalMerge pass while eliminating some merging that was not beneficial.
This feature allowed us to enable the GlobalMerge pass on RISC-V in our
downstream by default because it led to improvements on multiple
benchmark suites.

I plan to post a separate patch to propose enabling this by default on
RISC-V. But I do not want that discussion to be part of the discussion
of adding this feature, so I am keeping the patches separate.
5 files changed
tree: 9990595f73f762e11a1cc627fbd5ba4213cd7acc
  1. .ci/
  2. .github/
  3. bolt/
  4. clang/
  5. clang-tools-extra/
  6. cmake/
  7. compiler-rt/
  8. cross-project-tests/
  9. flang/
  10. libc/
  11. libclc/
  12. libcxx/
  13. libcxxabi/
  14. libunwind/
  15. lld/
  16. lldb/
  17. llvm/
  18. llvm-libgcc/
  19. mlir/
  20. offload/
  21. openmp/
  22. polly/
  23. pstl/
  24. runtimes/
  25. third-party/
  26. utils/
  27. .clang-format
  28. .clang-tidy
  29. .git-blame-ignore-revs
  30. .gitattributes
  31. .gitignore
  32. .mailmap
  33. CODE_OF_CONDUCT.md
  34. CONTRIBUTING.md
  35. LICENSE.TXT
  36. pyproject.toml
  37. README.md
  38. SECURITY.md
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