yosys/tests/opt/opt_reduce_bmux.ys

read_rtlil << EOT

module \top
  wire width 12 input 0 \A
  wire width 2 input 1 \S
  wire width 6 output 2 \Y

  cell $bmux $0
    parameter \WIDTH 6
    parameter \S_WIDTH 2
    connect \A { \A [11:10] \A [3:2] \A [10:9] \A [7] \A [7] \A [8] \A [2] \A [7:6] \A [5] \A [5] \A [3:2] \A [5:4] \A [1] \A [1] \A [3:0] }
    connect \S \S
    connect \Y \Y
  end
end

EOT

equiv_opt -assert opt_reduce -fine
opt_reduce -fine
select -assert-count 1 t:$bmux r:WIDTH=4 %i

design -reset

read_rtlil << EOT

module \top
  wire width 6 input 0 \A
  wire width 2 input 1 \S
  wire width 6 output 2 \Y

  cell $bmux $0
    parameter \WIDTH 6
    parameter \S_WIDTH 2
    connect \A { \A [5:0] \A [5:0] \A [5:0] \A [5:0] }
    connect \S \S
    connect \Y \Y
  end
end

EOT

equiv_opt -assert opt_reduce -fine
opt_reduce -fine
select -assert-count 0 t:$bmux

design -reset

read_rtlil << EOT

module \top
  wire width 160 input 0 \A
  wire width 2 input 1 \S
  wire width 5 output 2 \Y

  cell $bmux $0
    parameter \WIDTH 5
    parameter \S_WIDTH 5
    connect \A \A
    connect \S { \S [1] 1'1 \S [0] \S [1] 1'0 }
    connect \Y \Y
  end
end

EOT

equiv_opt -assert opt_reduce -fine
opt_reduce -fine
select -assert-count 1 t:$bmux r:S_WIDTH=2 %i

design -reset

read_rtlil << EOT

module \top
  wire width 10 input 0 \A
  wire input 1 \S
  wire width 5 output 2 \Y

  cell $bmux $0
    parameter \WIDTH 5
    parameter \S_WIDTH 1
    connect \A \A
    connect \S \S
    connect \Y \Y
  end
end

EOT

equiv_opt -assert opt_reduce -fine
opt_reduce -fine
select -assert-count 0 t:$bmux
select -assert-count 1 t:$mux

design -reset

read_rtlil << EOT

module \top
  wire width 5 input 0 \A
  wire width 5 output 1 \Y

  cell $bmux $0
    parameter \WIDTH 5
    parameter \S_WIDTH 0
    connect \A \A
    connect \S { }
    connect \Y \Y
  end
end

EOT

equiv_opt -assert opt_reduce -fine
opt_reduce -fine
select -assert-count 0 t:$bmux