llvm-project

e4f06b20 - [LowerTypeTests] Append jump table aliases to llvm.used once (NFC) (#241146)

[LowerTypeTests] Append jump table aliases to llvm.used once (NFC) (#241146) buildBitSetsFromFunctionsNative called appendToUsed for each non-canonical, non-exported jump table alias. Each call rebuilt llvm.used from scratch and left the old initializer behind as a dead ConstantArray that still used all of its elements, so N aliases took quadratic time and left O(N^2) dead uses on the aliases. Walking those uses (e.g. in the verifier) cost a lot of build time. Append the aliases just once after the loop instead. There's no change to the output, but we remove the quadratic behavior. For a large internal link with FullLTO and cross-DSO CFI, this change reduced the overall link time from 24 minutes to 18 minutes, and peak RSS from 51 GiB to 28 GiB. Assisted-by: Claude Opus 5.5 Co-authored-by: Nathan Lanza <nathanlanza@gmail.com>