llvm-project

3f5d17b2 - [SLP]Vectorize bool-to-bitmask reductions as a bitcast of zero tests

[SLP]Vectorize bool-to-bitmask reductions as a bitcast of zero tests An or-reduction of boolean leaves each shifted by their own bit position (an array of bools packed into a bitmask) is a bitcast of the per-lane zero tests to an integer, which the backend lowers to a movmsk (X86). Emit that instead of the shift and reduce sequence when it is cheaper. Fixes #41997 Assisted-by: Cursor Reviewers: RKSimon Pull Request: https://github.com/llvm/llvm-project/pull/223434