In r202512 I fixed a bug in B3::Procedure::resetReachability(), but this fix was more complicated than need be. There was one set of data structures for the set of live basic blocks, and another for the set of live values - even though the set of blocks determined the set of values.
Created attachment 282171 [details] the patch
Comment on attachment 282171 [details] the patch r=me
Landed in https://trac.webkit.org/changeset/202518