opt_reduce - simplify large MUXes and AND/OR gates

yosys> help opt_reduce
opt_reduce [options] [selection]
This pass performs two interlinked optimizations:

1. it consolidates trees of large AND gates or OR gates and eliminates
duplicated inputs.

2. it identifies duplicated inputs to MUXes and replaces them with a single
input with the original control signals OR'ed together.
perform fine-grain optimizations
alias for -fine