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Fix splitfanout

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This commit is contained in:
Akash Levy 2024-08-14 13:19:58 -07:00
parent 63a421aed8
commit 83dfdd9dd5
1 changed files with 23 additions and 30 deletions
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53
passes/cmds/splitfanout.cc
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@ -71,22 +71,23 @@ struct SplitfanoutWorker
// Get output signal/port
SigSpec outsig;
IdString outport;
if (cell->hasPort(ID::Y)) {
outsig = sigmap(cell->getPort(ID::Y));
outport = ID::Y;
}
else if (cell->hasPort(ID::Q)) {
outsig = sigmap(cell->getPort(ID::Q));
outport = ID::Q;
}
else
int output_count = 0;
for (auto conn : cell->connections())
if (cell->output(conn.first)) {
output_count++;
outport = conn.first;
outsig = conn.second;
}
if (output_count != 1) {
log("Skipping %s cell %s/%s with %d output ports.\n", log_id(cell->type), log_id(module), log_id(cell), output_count);
return 0;
}
// Check if output signal is "bit-split", skip if so
pool<tuple<IdString,IdString,int>> bit_users = bit_users_db[outsig[0]];
auto bit_users = bit_users_db[outsig[0]];
for (int i = 0; i < GetSize(outsig); i++) {
if (bit_users_db[outsig[i]] != bit_users) {
log(" Skipping %s cell %s/%s with bit-split output.\n", log_id(cell->type), log_id(module), log_id(cell));
log("Skipping %s cell %s/%s with bit-split output.\n", log_id(cell->type), log_id(module), log_id(cell));
return 0;
}
}
@ -98,37 +99,29 @@ struct SplitfanoutWorker
// Iterate over bit users and create a new cell for each one
log("Splitting %s cell %s/%s into %d copies based on fanout:\n", log_id(cell->type), log_id(module), log_id(cell), GetSize(bit_users)-1);
int foi = 0;
cell->setPort(outport, module->addWire(NEW_ID, GetSize(outsig))); // disconnect the original cell (to be deleted)
for (auto user : bit_users)
cell->unsetPort(outport);
for (auto bit_user : bit_users)
{
// Create a new cell
IdString new_name = module->uniquify(cell->name.str());
Cell *new_cell = module->addCell(new_name, cell);
// Connect the new cell to the user
if (std::get<1>(user) == IdString()) {
IdString old_name = std::get<0>(user);
IdString new_name = module->uniquify(old_name.str());
Wire *old_wire = module->wire(old_name);
Wire *new_wire = module->addWire(new_name, old_wire);
module->swap_names(old_wire, new_wire);
old_wire->port_input = false;
old_wire->port_output = false;
new_cell->setPort(outport, new_wire);
if (std::get<1>(bit_user) == IdString()) { // is wire
Wire *wire = module->wire(std::get<0>(bit_user));
SigSpec spec(wire, std::get<2>(bit_user), GetSize(outsig));
new_cell->setPort(outport, spec);
}
else {
Wire *new_wire = module->addWire(NEW_ID, GetSize(outsig));
SigSpec sig = module->cell(std::get<0>(user))->getPort(std::get<1>(user));
sig.replace(std::get<2>(user), new_wire);
module->cell(std::get<0>(user))->setPort(std::get<1>(user), sig);
SigSpec sig = module->cell(std::get<0>(bit_user))->getPort(std::get<1>(bit_user));
sig.replace(std::get<2>(bit_user), new_wire);
module->cell(std::get<0>(bit_user))->setPort(std::get<1>(bit_user), sig);
new_cell->setPort(outport, new_wire);
}
// Log the new cell
log(" slice %d: %s => %s\n", foi, log_id(new_name), log_signal(new_cell->getPort(outport)));
// Increment the fanout index
foi++;
log(" slice %d: %s => %s\n", foi++, log_id(new_name), log_signal(new_cell->getPort(outport)));
}
// Remove the original cell