llvm-project

ac78ce36 - [flang][AliasAnalysis] Add opt-in getSource memoization cache (#208319)

[flang][AliasAnalysis] Add opt-in getSource memoization cache (#208319) Add an opt-in cache to fir::AliasAnalysis that memoizes getSource() results keyed on (value, flags). Caching is off by default and turned on via enableSourceCache(); getSource() becomes a thin wrapper over the uncached getSourceImpl(). The cache is a frozen snapshot with no automatic invalidation and lives no longer than the AliasAnalysis instance, so a client enables it only for a region in which it does not mutate IR in a way that would change a source. Flang's LICM enables the cache on its fir::AliasAnalysis before adding it to the mlir::AliasAnalysis aggregate: LICM only moves operations, so getSource()'s inputs are unchanged across the hoists, and the pass manager drops the analysis (and its cache) after the pass. Add a unit test covering the default-off behavior, cache fill/hit, and that disableSourceCache() clears and bypasses the cache. Assisted-by: Cursor