The answers to this question say that Altera Quartus will generate block diagrams from Verilog files. I'm a user of Quartus Prime Lite Edition. How do I generate block diagrams?
Seeing that you're using a Lite version of Quartus, maybe you don't actually are interested in Altera synthesis, but more in general Verilog analysis and clever code optimization.
You might want to have a look at Yosys, which supports generating the graphs I think you want, is free, much easier on your RAM and CPU than Quartus and frankly, produces better optimized/analyzed verilog/netlists.
For example, take this code:
module piggybank ( input clk, input reset, input [8:0] deposit, input [8:0] withdrawal, output [16:0] balance, output success ); reg [16:0] _balance; assign balance = _balance; wire [8:0] interest = _balance [16:9]; reg [5:0] time_o_clock; localparam STATE_OPEN = 0; localparam STATE_CLOSED = 1; reg openness; assign success = (deposit == 0 && withdrawal == 0) || (openness == STATE_OPEN && (withdrawal <= _balance)); always @(posedge clk) if(reset) begin _balance <= 0; openness <= STATE_CLOSED; time_o_clock <= 0; end else begin if (openness == STATE_CLOSED) begin if(time_o_clock == 5'd7) begin openness <= STATE_OPEN; time_o_clock <= 0; end else begin time_o_clock <= time_o_clock + 1; end if (time_o_clock == 0) begin //add interest at closing _balance <= _balance + interest; end; end else begin //We're open! if(time_o_clock == 5'd9) begin // open for 9h openness <= STATE_CLOSED; time_o_clock <= 0; end else begin _balance <= (success) ? _balance + deposit - withdrawal : _balance; time_o_clock <= time_o_clock + 1; end end // else: !if(openness == STATE_CLOSED) end // else: !if(reset) endmodule // piggybank
and run it throug yosys:
yosys> read_verilog minifsm.v yosys> show
you get the raw, unoptimized, interpretation of the Verilog code:
After employing yosys' analysis and optimization methods, you get the image from the answer mentioned above:
As you can see, these are pretty different. Things get a lot more complicated when you tell yosys to actually synthesize for an actual technology, using the appropriate mappings: