Optimize functions inlined from packages in Dfg (#7091)

test_regress/t/t_dfg_synthesis.v

@@ -6,6 +6,12 @@
 
 `define signal(name, expr) wire [$bits(expr)-1:0] ``name = expr
 
+package pkg;
+  function automatic logic [7:0] sub(input logic [7:0] a, input logic [7:0] b);
+    return a - b;
+  endfunction
+endpackage
+
 module t (
 `include "portlist.vh" // Boilerplate generated by t_dfg_break_cycles.py
   rand_a, rand_b, srand_a, srand_b
@@ -524,4 +530,19 @@ module t (
   end
   `signal(USES_LOOP_VAR, uses_loop_var);
 
+  function automatic logic [7:0] add(input logic [7:0] a, input logic [7:0] b);
+    return a + b;
+  endfunction
+  logic [7:0] func_1;
+  always_comb begin
+    func_1 = add(rand_a[7:0], rand_b[7:0]);
+  end
+  `signal(FUNC_1, func_1);
+
+  logic [7:0] func_2;
+  always_comb begin
+    func_2 = pkg::sub(rand_a[7:0], rand_b[7:0]);
+  end
+  `signal(FUNC_2, func_2);
+
 endmodule