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Fix all undef-muxes in dlatch input cone

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This commit is contained in:
Clifford Wolf 2016-06-02 14:37:07 +02:00
parent adfc80727c
commit d2695e2bfa
1 changed files with 73 additions and 35 deletions
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108
passes/proc/proc_dlatch.cc
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@ -33,7 +33,7 @@ struct proc_dlatch_db_t
Module *module;
SigMap sigmap;
pool<Cell*> rewritten_mux_cells;
pool<Cell*> generated_dlatches;
dict<Cell*, vector<SigBit>> mux_srcbits;
dict<SigBit, pair<Cell*, int>> mux_drivers;
dict<SigBit, int> sigusers;
@ -190,7 +190,6 @@ struct proc_dlatch_db_t
int n = find_mux_feedback(sig_a[index], needle, set_undef);
if (n != false_node) {
if (set_undef && sig_a[index] == needle) {
rewritten_mux_cells.insert(cell);
SigSpec sig = cell->getPort("\\A");
sig[index] = State::Sx;
cell->setPort("\\A", sig);
@ -204,7 +203,6 @@ struct proc_dlatch_db_t
n = find_mux_feedback(sig_b[i*width + index], needle, set_undef);
if (n != false_node) {
if (set_undef && sig_b[i*width + index] == needle) {
rewritten_mux_cells.insert(cell);
SigSpec sig = cell->getPort("\\B");
sig[i*width + index] = State::Sx;
cell->setPort("\\B", sig);
@ -257,43 +255,81 @@ struct proc_dlatch_db_t
return and_bits[0];
}
void fixup_rewritten_muxes()
void fixup_mux(Cell *cell)
{
for (auto cell : rewritten_mux_cells)
SigSpec sig_a = cell->getPort("\\A");
SigSpec sig_b = cell->getPort("\\B");
SigSpec sig_s = cell->getPort("\\S");
SigSpec sig_any_valid_b;
SigSpec sig_new_b, sig_new_s;
for (int i = 0; i < GetSize(sig_s); i++) {
SigSpec b = sig_b.extract(i*GetSize(sig_a), GetSize(sig_a));
if (!b.is_fully_undef()) {
sig_any_valid_b = b;
sig_new_b.append(b);
sig_new_s.append(sig_s[i]);
}
}
if (sig_new_s.empty()) {
sig_new_b = sig_a;
sig_new_s = State::S0;
}
if (sig_a.is_fully_undef() && !sig_any_valid_b.empty())
cell->setPort("\\A", sig_any_valid_b);
if (GetSize(sig_new_s) == 1) {
cell->type = "$mux";
cell->unsetParam("\\S_WIDTH");
} else {
cell->type = "$pmux";
cell->setParam("\\S_WIDTH", GetSize(sig_new_s));
}
cell->setPort("\\B", sig_new_b);
cell->setPort("\\S", sig_new_s);
}
void fixup_muxes()
{
pool<Cell*> visited, queue;
dict<Cell*, pool<SigBit>> upstream_cell2net;
dict<SigBit, pool<Cell*>> upstream_net2cell;
CellTypes ct;
ct.setup_internals();
for (auto cell : module->cells())
for (auto conn : cell->connections()) {
if (cell->input(conn.first))
for (auto bit : sigmap(conn.second))
upstream_cell2net[cell].insert(bit);
if (cell->output(conn.first))
for (auto bit : sigmap(conn.second))
upstream_net2cell[bit].insert(cell);
}
queue = generated_dlatches;
while (!queue.empty())
{
SigSpec sig_a = cell->getPort("\\A");
SigSpec sig_b = cell->getPort("\\B");
SigSpec sig_s = cell->getPort("\\S");
SigSpec sig_any_valid_b;
pool<Cell*> next_queue;
SigSpec sig_new_b, sig_new_s;
for (int i = 0; i < GetSize(sig_s); i++) {
SigSpec b = sig_b.extract(i*GetSize(sig_a), GetSize(sig_a));
if (!b.is_fully_undef()) {
sig_any_valid_b = b;
sig_new_b.append(b);
sig_new_s.append(sig_s[i]);
}
for (auto cell : queue) {
if (cell->type.in("$mux", "$pmux"))
fixup_mux(cell);
for (auto bit : upstream_cell2net[cell])
for (auto cell : upstream_net2cell[bit])
next_queue.insert(cell);
visited.insert(cell);
}
if (sig_new_s.empty()) {
sig_new_b = sig_a;
sig_new_s = State::S0;
queue.clear();
for (auto cell : next_queue) {
if (!visited.count(cell) && ct.cell_known(cell->type))
queue.insert(cell);
}
if (sig_a.is_fully_undef() && !sig_any_valid_b.empty())
cell->setPort("\\A", sig_any_valid_b);
if (GetSize(sig_new_s) == 1) {
cell->type = "$mux";
cell->unsetParam("\\S_WIDTH");
} else {
cell->type = "$pmux";
cell->setParam("\\S_WIDTH", GetSize(sig_new_s));
}
cell->setPort("\\B", sig_new_b);
cell->setPort("\\S", sig_new_s);
}
}
};
@ -370,6 +406,8 @@ void proc_dlatch(proc_dlatch_db_t &db, RTLIL::Process *proc)
SigSpec rhs = latches_bits.second.extract(offset, width);
Cell *cell = db.module->addDlatch(NEW_ID, db.module->Not(NEW_ID, db.make_hold(n)), rhs, lhs);
db.generated_dlatches.insert(cell);
log("Latch inferred for signal `%s.%s' from process `%s.%s': %s\n",
db.module->name.c_str(), log_signal(lhs), db.module->name.c_str(), proc->name.c_str(), log_id(cell));
}
@ -403,7 +441,7 @@ struct ProcDlatchPass : public Pass {
for (auto &proc_it : module->processes)
if (design->selected(module, proc_it.second))
proc_dlatch(db, proc_it.second);
db.fixup_rewritten_muxes();
db.fixup_muxes();
}
}
} ProcDlatchPass;