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.

-fine

perform fine-grain optimizations

-full

alias for -fine