iopadmap: Refactor and fix tristate buffer mapping. (#1527)

The previous code for rerouting wires when inserting tristate buffers
was overcomplicated and didn't handle all cases correctly (in
particular, only cell connections were rewired — internal connections
were not).

1 files changed, 99 insertions, 0 deletions

diff --git a/tests/techmap/iopadmap.ys b/tests/techmap/iopadmap.ys
new file mode 100644
index 000000000..f4345e906
--- /dev/null
+++ b/tests/techmap/iopadmap.ys
@@ -0,0 +1,99 @@
+read_verilog << EOT
+module ibuf ((* iopad_external_pin *) input i, output o); endmodule
+module obuf (input i, (* iopad_external_pin *) output o); endmodule
+module obuft (input i, input oe, (* iopad_external_pin *) output o); endmodule
+module iobuf (input i, input oe, output o, (* iopad_external_pin *) inout io); endmodule
+
+module a(input i, output o);
+assign o = i;
+endmodule
+
+module b(input i, output o);
+assign o = i;
+ibuf b (.i(i), .o(o));
+endmodule
+
+module c(input i, output o);
+obuf b (.i(i), .o(o));
+endmodule
+
+module d(input i, oe, output o, o2, o3);
+assign o = oe ? i : 1'bz;
+assign o2 = o;
+assign o3 = ~o;
+endmodule
+
+module e(input i, oe, inout io, output o2, o3);
+assign io = oe ? i : 1'bz;
+assign o2 = io;
+assign o3 = ~io;
+endmodule
+EOT
+
+opt_clean
+tribuf
+simplemap
+iopadmap -bits -inpad ibuf o:i -outpad obuf i:o -toutpad obuft oe:i:o -tinoutpad iobuf oe:o:i:io
+opt_clean
+
+select -assert-count 1 a/t:ibuf
+select -assert-count 1 a/t:obuf
+select -set ib w:i %a %co a/t:ibuf %i
+select -set ob w:o %a %ci a/t:obuf %i
+select -assert-count 1 @ib
+select -assert-count 1 @ob
+select -assert-count 1 @ib %co %co @ob %i
+
+select -assert-count 1 b/t:ibuf
+select -assert-count 1 b/t:obuf
+select -set ib w:i %a %co b/t:ibuf %i
+select -set ob w:o %a %ci b/t:obuf %i
+select -assert-count 1 @ib
+select -assert-count 1 @ob
+select -assert-count 1 @ib %co %co @ob %i
+
+select -assert-count 1 c/t:ibuf
+select -assert-count 1 c/t:obuf
+select -set ib w:i %a %co c/t:ibuf %i
+select -set ob w:o %a %ci c/t:obuf %i
+select -assert-count 1 @ib
+select -assert-count 1 @ob
+select -assert-count 1 @ib %co %co @ob %i
+
+select -assert-count 2 d/t:ibuf
+select -assert-count 2 d/t:obuf
+select -assert-count 1 d/t:obuft
+select -set ib w:i %a %co d/t:ibuf %i
+select -set oeb w:oe %a %co d/t:ibuf %i
+select -set ob w:o %a %ci d/t:obuft %i
+select -set o2b w:o2 %a %ci d/t:obuf %i
+select -set o3b w:o3 %a %ci d/t:obuf %i
+select -assert-count 1 @ib
+select -assert-count 1 @oeb
+select -assert-count 1 @ob
+select -assert-count 1 @o2b
+select -assert-count 1 @o3b
+select -assert-count 1 @ib %co %co @ob %i
+select -assert-count 1 @oeb %co %co @ob %i
+select -assert-count 1 @ib %co %co @o2b %i
+select -assert-count 1 @ib %co %co t:$_NOT_ %i
+select -assert-count 1 @o3b %ci %ci t:$_NOT_ %i
+
+select -assert-count 2 e/t:ibuf
+select -assert-count 2 e/t:obuf
+select -assert-count 1 e/t:iobuf
+select -set ib w:i %a %co e/t:ibuf %i
+select -set oeb w:oe %a %co e/t:ibuf %i
+select -set iob w:io %a %ci e/t:iobuf %i
+select -set o2b w:o2 %a %ci e/t:obuf %i
+select -set o3b w:o3 %a %ci e/t:obuf %i
+select -assert-count 1 @ib
+select -assert-count 1 @oeb
+select -assert-count 1 @iob
+select -assert-count 1 @o2b
+select -assert-count 1 @o3b
+select -assert-count 1 @ib %co %co @iob %i
+select -assert-count 1 @oeb %co %co @iob %i
+select -assert-count 1 @iob %co %co @o2b %i
+select -assert-count 1 @iob %co %co t:$_NOT_ %i
+select -assert-count 1 @o3b %ci %ci t:$_NOT_ %i