improve clkbuf_inhibit propagation upwards through hierarchy

passes/techmap/clkbufmap.cc

@@ -166,13 +166,24 @@ struct ClkbufmapPass : public Pass {
 
 			// Insert buffers.
 			std::vector<pair<Wire *, Wire *>> input_queue;
-			for (auto wire : module->selected_wires())
+			// Copy current wire list, as we will be adding new ones during iteration.
+			std::vector<Wire *> wires(module->wires());
+			for (auto wire : wires)
 			{
 				// Should not happen.
 				if (wire->port_input && wire->port_output)
 					continue;
+				bool process_wire = module->selected(wire);
 				if (!select && wire->get_bool_attribute("\\clkbuf_inhibit"))
+					process_wire = false;
+				if (!process_wire) {
+					// This wire is supposed to be bypassed, so make sure we don't buffer it in
+					// some buffer higher up in the hierarchy.
+					if (wire->port_output)
+						for (int i = 0; i < GetSize(wire); i++)
+							buf_ports.insert(make_pair(module->name, make_pair(wire->name, i)));
 					continue;
+				}
 
 				pool<int> input_bits;
 

tests/techmap/clkbufmap.ys

@@ -3,11 +3,26 @@ 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 clkgen (output o); endmodule
 
-module top(input clk1, clk2, clk3, d, e, output [2:0] q);
+module top(input clk1, clk2, clk3, d, e, output [4:0] q);
+wire clk4, clk5, clk6;
 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]));
+sub s3 (.sclk4(clk4), .sclk5(clk5), .sclk6(clk6), .sd(d), .sq(q[3]));
+dff s4 (.clk(clk4), .d(d), .q(q[4]));
+dff s5 (.clk(clk5), .d(d), .q(q[4]));
+dff s6 (.clk(clk6), .d(d), .q(q[4]));
+endmodule
+
+module sub(output sclk4, output sclk5, output sclk6, input sd, output sq);
+wire tmp;
+clkgen s7(.o(sclk4));
+clkgen s8(.o(sclk5));
+clkgen s9(.o(tmp));
+clkbuf s10(.i(tmp), .o(sclk6));
+dff s11(.clk(sclk4), .d(sd), .q(sq));
 endmodule
 EOT
 
@@ -18,7 +33,8 @@ design -save ref
 
 design -load ref
 clkbufmap -buf clkbuf o:i
-select -assert-count 2 t:clkbuf
+select -assert-count 3 top/t:clkbuf
+select -assert-count 2 sub/t:clkbuf
 select -set clk1 w:clk1 %a %co t:clkbuf %i          # Find 'clk1' fanouts that are 'clkbuf'
 select -assert-count 1 @clk1                        # Check there is one such fanout
 select -assert-count 1 @clk1 %x:+[o] %co c:s* %i    # Check that the 'o' of that clkbuf drives one fanout
@@ -27,6 +43,14 @@ select -set clk2 w:clk2 %a %co t:clkbuf %i
 select -assert-count 1 @clk2
 select -assert-count 1 @clk2 %x:+[o] %co c:s* %i
 select -assert-count 1 @clk2 %x:+[o] %co c:s1 %i
+select -set clk5 w:clk5 %a %ci t:clkbuf %i
+select -assert-count 1 @clk5
+select -assert-count 1 @clk5 %x:+[o] %co c:s5 %i
+select -assert-count 1 @clk5 %x:+[i] %ci c:s3 %i
+select -set sclk4 w:sclk4 %a %ci t:clkbuf %i
+select -assert-count 1 @sclk4
+select -assert-count 1 @sclk4 %x:+[o] %co c:s11 %i
+select -assert-count 1 @sclk4 %x:+[i] %ci c:s7 %i
 
 # ----------------------
 
@@ -34,7 +58,7 @@ 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 t:clkbuf
+select -assert-count 2 top/t:clkbuf
 select -set clk1 w:clk1 %a %co t:clkbuf %i          # Find 'clk1' fanouts that are 'clkbuf'
 select -assert-count 1 @clk1                        # Check there is one such fanout
 select -assert-count 1 @clk1 %x:+[o] %co c:s* %i    # Check that the 'o' of that clkbuf drives one fanout
@@ -47,7 +71,8 @@ design -load ref
 setattr -set clkbuf_inhibit 1 w:clk1
 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 2 t:clkbuf
+select -assert-count 3 top/t:clkbuf
+select -assert-count 2 sub/t:clkbuf
 select -set clk1 w:clk1 %a %co t:clkbuf %i          # Find 'clk1' fanouts that are 'clkbuf'
 select -assert-count 1 @clk1                        # Check there is one such fanout
 select -assert-count 1 @clk1 %x:+[o] %co c:s* %i    # Check that the 'o' of that clkbuf drives one fanout
@@ -62,7 +87,10 @@ select -assert-count 1 @clk2 %x:+[o] %co c:s1 %i    # And that one fanout is 's0
 design -load ref
 setattr -set buffer_type "none" w:clk1
 setattr -set buffer_type "bufr" w:clk2
+setattr -set buffer_type "bufr" w:sclk4
+setattr -set buffer_type "bufr" w:sclk5
 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
+select -assert-count 0 top/t:clkbuf
+select -assert-count 1 sub/t:clkbuf