Commits
Michael Gottesman committed 40760685c3c
Revert "Revert "[sil-combine] ({struct_extract,unchecked_enum_data} (unchecked_ref_bit_cast)) -> unchecked_ref_bit_cast when the two instructions are just layout compatible bit casts.""
This reapplies commit r21164 by reverting r21169.
Swift SVN r21224