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llvm / llvm-project / 0b71d8020f1181c75c305d34943ed42bb1948177
commit0b71d8020f1181c75c305d34943ed42bb1948177[log] [tgz]
authorJeremy Morse <jeremy.morse@sony.com>Wed Jul 17 11:25:08 2024 +0100
committerGitHub <noreply@github.com>Wed Jul 17 11:25:08 2024 +0100
treee4944014b21461a28165742697baf9db09a6daee
parent9b9194af408003e7d484d621fb3ee61389bdd20e [diff]
[InstrRef][NFC] Avoid un-necessary DenseMap queries (#99048)

This patch adjusts how some data is stored to avoid a number of
un-necessary DenseMap queries. There's no change to the compiler
behaviour, and it's measurably faster on the compile time tracker.

The BlockOrders vector in buildVLocValueMap collects the blocks over
which a variables value have to be determined: however the Cmp ordering
function makes two DenseMap queries to determine the RPO-order of blocks
being compared. And given that sorting is O(N log(N)) comparisons this
isn't fast. So instead, fetch the RPO-numbers of the block collection,
order those, and then map back to the blocks themselves.

The OrderToBB collection mapped an RPO-number to an MBB: it's completely
un-necessary to have DenseMap here, we can just use the RPO number as an
array index. Switch it to a SmallVector and deal with a few consequences
when iterating.

(And for good measure I've jammed in a couple of reserve calls).
2 files changed
tree: e4944014b21461a28165742697baf9db09a6daee
  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
README.md

The LLVM Compiler Infrastructure

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