Added constant-clock case to opt_rmdff

diff --git a/passes/opt/opt_rmdff.cc b/passes/opt/opt_rmdff.cc
index 9ce98004ebab09c7e2a80e2209aacea17ceb8409..a8e2c4121895297701f67075853d296c61f59351 100644 (file)
--- a/passes/opt/opt_rmdff.cc
+++ b/passes/opt/opt_rmdff.cc
@@ -92,6 +92,14 @@ static bool handle_dff(RTLIL::Module *mod, RTLIL::Cell *dff)
                }
        }
 
+       if (sig_c.is_fully_const()) {
+               if (val_rv.bits.size() == 0)
+                       val_rv = RTLIL::Const(RTLIL::State::Sx, sig_q.width);
+               RTLIL::SigSig conn(sig_q, val_rv);
+               mod->connections.push_back(conn);
+               goto delete_dff;
+       }
+
        if (sig_d.is_fully_undef() && sig_d.width == int(val_rv.bits.size())) {
                RTLIL::SigSig conn(sig_q, val_rv);
                mod->connections.push_back(conn);