diff options
Diffstat (limited to 'passes/opt/opt_rmdff.cc')
| -rw-r--r-- | passes/opt/opt_rmdff.cc | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/passes/opt/opt_rmdff.cc b/passes/opt/opt_rmdff.cc index fa954afac..7e87d1adc 100644 --- a/passes/opt/opt_rmdff.cc +++ b/passes/opt/opt_rmdff.cc @@ -29,6 +29,7 @@ PRIVATE_NAMESPACE_BEGIN SigMap assign_map, dff_init_map; SigSet<RTLIL::Cell*> mux_drivers; dict<SigBit, pool<SigBit>> init_attributes; +bool keepdc; void remove_init_attr(SigSpec sig) { @@ -115,7 +116,7 @@ bool handle_dff(RTLIL::Module *mod, RTLIL::Cell *dff) bool has_init = false; RTLIL::Const val_init; for (auto bit : dff_init_map(sig_q).to_sigbit_vector()) { - if (bit.wire == NULL) + if (bit.wire == NULL || keepdc) has_init = true; val_init.bits.push_back(bit.wire == NULL ? bit.data : RTLIL::State::Sx); } @@ -182,7 +183,7 @@ struct OptRmdffPass : public Pass { { // |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---| log("\n"); - log(" opt_rmdff [selection]\n"); + log(" opt_rmdff [-keepdc] [selection]\n"); log("\n"); log("This pass identifies flip-flops with constant inputs and replaces them with\n"); log("a constant driver.\n"); @@ -193,7 +194,17 @@ struct OptRmdffPass : public Pass { int total_count = 0, total_initdrv = 0; log_header(design, "Executing OPT_RMDFF pass (remove dff with constant values).\n"); - extra_args(args, 1, design); + keepdc = false; + + size_t argidx; + for (argidx = 1; argidx < args.size(); argidx++) { + if (args[argidx] == "-keepdc") { + keepdc = true; + continue; + } + break; + } + extra_args(args, argidx, design); for (auto module : design->selected_modules()) { |