Straighforward API to build pruned liveness from a single SSA value.
This 3-line function allows PrunedLiveness to be used anywhere
ValueLifetimeAnalysis was used in OSSA form. Aside from simplicity and
efficiency, the difference is that this composes with other utilities
that only care about PrunedLiveBlocks, PrunedLiveness, or
PrunesLivenessBounary independent of how those data structures were generated.
Simple wrapper to compute the boundary of PrunedLiveness.
Pervasively useful utility for working with OSSA reference lifetimes
and borrow scopes.
This can also replace the implementation in
CanonicalOSSALifetime. This will greatly simplify that utility's
logic, preparing it to handle diagnostics (like move-only SILValue
checking) and other features.
