optimize branch: match_op.hpp: revert back to ecaf483a1 (simpler and just as fast).
optimize branch:
match_op.hpp: revert back to ecaf483a1 (simpler and just as fast).

kaskr/CppAD,kaskr/CppAD,kaskr/CppAD,kaskr/CppAD,kaskr/CppAD