--- /dev/null
+read_verilog <<EOT
+module clkbuf (input i, (* clkbuf_driver *) output o); endmodule
+module dff ((* clkbuf_sink *) input clk, input d, output q); endmodule
+module dffe ((* clkbuf_sink *) input c, input d, e, output q); endmodule
+module latch (input e, d, output q); endmodule
+
+module top(input clk1, clk2, clk3, d, e, output [2:0] q);
+dff s0 (.clk(clk1), .d(d), .q(q[0]));
+dffe s1 (.c(clk2), .d(d), .e(e), .q(q[1]));
+latch s2 (.e(clk3), .d(d), .q(q[2]));
+endmodule
+EOT
+
+hierarchy -auto-top
+design -save ref
+
+# ----------------------
+
+design -load ref
+clkbufmap -buf clkbuf o:i
+select -assert-count 1 w:clk1 %a %co t:clkbuf %i
+select -assert-count 1 w:clk2 %a %co t:clkbuf %i
+select -assert-count 2 t:clkbuf
+
+# ----------------------
+
+design -load ref
+setattr -set clkbuf_inhibit 0 w:clk1
+setattr -set clkbuf_inhibit 1 w:clk2
+clkbufmap -buf clkbuf o:i
+select -assert-count 1 w:clk1 %a %co t:clkbuf %i
+select -assert-count 0 w:clk2 %a %co t:clkbuf %i
+select -assert-count 1 t:clkbuf
+
+# ----------------------
+
+design -load ref
+setattr -set buffer_type "bufg" w:clk2
+clkbufmap -buf clkbuf o:i w:* a:buffer_type=none a:buffer_type=bufr %u %d
+select -assert-count 1 w:clk1 %a %co t:clkbuf %i
+select -assert-count 1 w:clk2 %a %co t:clkbuf %i
+select -assert-count 2 t:clkbuf
+
+# ----------------------
+
+design -load ref
+setattr -set buffer_type "none" w:clk1
+setattr -set buffer_type "bufr" w:clk2
+clkbufmap -buf clkbuf o:i w:* a:buffer_type=none a:buffer_type=bufr %u %d
+select -assert-count 0 w:clk1 %a %co t:clkbuf %i
+select -assert-count 0 w:clk2 %a %co t:clkbuf %i
+select -assert-count 0 t:clkbuf