[mlir][AliasAnalysis] Add opt-in query caching; use it in flang LICM

Add a generic, opt-in query-caching capability to the mlir::AliasAnalysis
aggregator. The aggregator gains a public RAII QueryCacheScope and private
enable/disableQueryCaching() fan-out; the Concept gains enableQueryCaching()/
disableQueryCaching() and the Model forwards them to implementations that
provide enableSourceCache()/disableSourceCache() (detected via
llvm::is_detected) and no-ops otherwise, so existing implementations need no
changes and transformation passes never name a concrete implementation.

The FIR AliasAnalysis implements the hook by memoizing getSource(): getSource()
becomes a thin wrapper over getSourceImpl() that consults a frozen-snapshot
cache keyed on (value, flags) when caching is enabled.

Flang's LICM enables caching for the duration of the pass via QueryCacheScope.
This is sound because LICM only moves operations and getSource()'s
position-dependent inputs are already frozen for the pass run by the
AliasAnalysis's own dominance/scope caches, making caching observationally
equivalent to no caching across the hoists.

Assisted by Cursor
5 files changed
tree: 1b47dfc91e79d47853baad88f7711994d30c4cc5
  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

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