Optimize Swift Code

Make a measured Swift hot path cheaper without changing observable behavior. Each change applies one reference card to a cost that a profile attributes, is proven equivalent by an oracle, and is kept only if the metric the card names improves: malloc calls, retains, hash calls, an instruction pattern in SIL or assembly, or a benchmark percentile. Several cards record classic rewrites that measured as no difference because -O with whole-module optimization already did the work, so check the real build before rewriting.

Workflow