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Improved handling of reg init in opt_share and opt_rmdff

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This commit is contained in:
Clifford Wolf 2014-02-04 12:02:47 +01:00
parent 9e938aa32a
commit ecdf1f5577
2 changed files with 48 additions and 7 deletions
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36
passes/opt/opt_rmdff.cc
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@ -24,7 +24,7 @@
#include <stdlib.h>
#include <stdio.h>
static SigMap assign_map;
static SigMap assign_map, dff_init_map;
static SigSet<RTLIL::Cell*> mux_drivers;
static bool handle_dff(RTLIL::Module *mod, RTLIL::Cell *dff)
@ -73,6 +73,14 @@ static bool handle_dff(RTLIL::Module *mod, RTLIL::Cell *dff)
assign_map.apply(sig_c);
assign_map.apply(sig_r);
bool has_init;
RTLIL::Const val_init;
for (auto bit : dff_init_map(sig_q).to_sigbit_vector()) {
if (bit.wire == NULL)
has_init = true;
val_init.bits.push_back(bit.wire == NULL ? bit.data : RTLIL::State::Sx);
}
if (dff->type == "$dff" && mux_drivers.has(sig_d)) {
std::set<RTLIL::Cell*> muxes;
mux_drivers.find(sig_d, muxes);
@ -92,31 +100,41 @@ static bool handle_dff(RTLIL::Module *mod, RTLIL::Cell *dff)
}
}
if (sig_c.is_fully_const()) {
if (sig_c.is_fully_const() && (!sig_r.width || !has_init)) {
if (val_rv.bits.size() == 0)
val_rv = RTLIL::Const(RTLIL::State::Sx, sig_q.width);
val_rv = val_init;
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())) {
if (sig_d.is_fully_undef() && sig_r.width && !has_init) {
RTLIL::SigSig conn(sig_q, val_rv);
mod->connections.push_back(conn);
goto delete_dff;
}
if (sig_d.is_fully_const() && sig_r.width == 0) {
if (sig_d.is_fully_undef() && !sig_r.width && has_init) {
RTLIL::SigSig conn(sig_q, val_init);
mod->connections.push_back(conn);
goto delete_dff;
}
if (sig_d.is_fully_const() && !sig_r.width && !has_init) {
RTLIL::SigSig conn(sig_q, sig_d);
mod->connections.push_back(conn);
goto delete_dff;
}
if (sig_d == sig_q) {
if (sig_r.width > 0) {
if (sig_d == sig_q && !(sig_r.width && has_init)) {
if (sig_r.width) {
RTLIL::SigSig conn(sig_q, val_rv);
mod->connections.push_back(conn);
}
if (has_init) {
RTLIL::SigSig conn(sig_q, val_init);
mod->connections.push_back(conn);
}
goto delete_dff;
}
@ -155,6 +173,10 @@ struct OptRmdffPass : public Pass {
continue;
assign_map.set(mod_it.second);
dff_init_map.set(mod_it.second);
for (auto &it : mod_it.second->wires)
if (it.second->attributes.count("\\init") != 0)
dff_init_map.add(it.second, it.second->attributes.at("\\init"));
mux_drivers.clear();
std::vector<std::string> dff_list;