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router2: iteratively reserve arc driver wires, too (#1539)

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Lofty 2025-08-26 15:17:11 +01:00 committed by GitHub
parent ca4f727ffc
commit 0a7cbe1cd7
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1 changed files with 79 additions and 19 deletions
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98
common/route/router2.cc
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@ -430,6 +430,23 @@ struct Router2
}
}
// Returns true if a wire contains no sink port
bool is_wire_unusable(WireId wire, const NetInfo *net, const pool<WireId>& sink_wires, int iter_count = 0)
{
if (iter_count > 7)
return false; // heuristic to assume we've hit general routing
if (wire_data(wire).reserved_net != -1 && wire_data(wire).reserved_net != net->udata)
return true; // reserved for another net
if (sink_wires.count(wire))
return false;
for (auto p : ctx->getPipsDownhill(wire))
if (ctx->checkPipAvail(p)) {
if (!is_wire_unusable(ctx->getPipDstWire(p), net, sink_wires, iter_count + 1))
return false;
}
return true;
}
// Returns true if a wire contains no source ports or driving pips
bool is_wire_undriveable(WireId wire, const NetInfo *net, int iter_count = 0)
{
@ -458,33 +475,71 @@ struct Router2
return true;
}
// Find all the wires that must be used to route a given arc
bool reserve_wires_for_arc(NetInfo *net, store_index<PortRef> i)
// Find all the sink wires that must be used to route a given arc
bool reserve_driver_wires_for_arc(NetInfo *net, const pool<WireId>& sink_wires)
{
bool did_something = false;
WireId src = ctx->getNetinfoSourceWire(net);
{
auto &src_wd = wire_data(src);
if (src_wd.reserved_net != -1 && src_wd.reserved_net != net->udata)
log_error("attempting to reserve src wire '%s' for nets '%s' and '%s'\n", ctx->nameOfWire(src),
ctx->nameOf(nets_by_udata.at(src_wd.reserved_net)), ctx->nameOf(net));
src_wd.reserved_net = net->udata;
}
auto &usr = net->users.at(i);
for (auto sink : ctx->getNetinfoSinkWires(net, usr)) {
pool<WireId> rsv;
WireId cursor = sink;
if (!sink_wires.count(src) && !sink_wires.empty()) {
WireId cursor = src;
bool done = false;
if (ctx->debug)
log("reserving wires for arc %d (%s.%s) of net %s\n", i.idx(), ctx->nameOf(usr.cell),
ctx->nameOf(usr.port), ctx->nameOf(net));
if (ctx->debug) {
log("reserving wires for net %s\n", ctx->nameOf(net));
log(" with driver wire %s\n", ctx->nameOfWire(src));
}
while (!done) {
auto &wd = wire_data(cursor);
if (ctx->debug)
log(" %s\n", ctx->nameOfWire(cursor));
log(" %s (driver output)\n", ctx->nameOfWire(cursor));
did_something |= (wd.reserved_net != net->udata);
if (wd.reserved_net != -1 && wd.reserved_net != net->udata)
log_error("attempting to reserve wire '%s' for nets '%s' and '%s'\n", ctx->nameOfWire(cursor),
log_error("attempting to reserve driver output path wire '%s' for nets '%s' and '%s'\n", ctx->nameOfWire(cursor),
ctx->nameOf(nets_by_udata.at(wd.reserved_net)), ctx->nameOf(net));
wd.reserved_net = net->udata;
WireId next_cursor;
for (auto dh : ctx->getPipsDownhill(cursor)) {
WireId w = ctx->getPipDstWire(dh);
if (is_wire_unusable(w, net, sink_wires))
continue;
if (next_cursor != WireId() || sink_wires.count(w)) {
done = true;
break;
}
next_cursor = w;
}
if (next_cursor == WireId())
break;
cursor = next_cursor;
}
}
return did_something;
}
// Find all the sink wires that must be used to route a given arc
bool reserve_sink_wires_for_arc(NetInfo *net, store_index<PortRef> i)
{
bool did_something = false;
WireId src = ctx->getNetinfoSourceWire(net);
auto &usr = net->users.at(i);
for (auto sink : ctx->getNetinfoSinkWires(net, usr)) {
WireId cursor = sink;
bool done = false;
if (ctx->debug) {
log("reserving wires for arc %d (%s.%s) of net %s\n", i.idx(), ctx->nameOf(usr.cell),
ctx->nameOf(usr.port), ctx->nameOf(net));
log(" with sink wire %s\n", ctx->nameOfWire(sink));
}
while (!done) {
auto &wd = wire_data(cursor);
if (ctx->debug)
log(" %s (sink input)\n", ctx->nameOfWire(cursor));
did_something |= (wd.reserved_net != net->udata);
if (wd.reserved_net != -1 && wd.reserved_net != net->udata)
log_error("attempting to reserve sink input path wire '%s' for nets '%s' and '%s'\n", ctx->nameOfWire(cursor),
ctx->nameOf(nets_by_udata.at(wd.reserved_net)), ctx->nameOf(net));
wd.reserved_net = net->udata;
if (cursor == src)
@ -518,8 +573,13 @@ struct Router2
WireId src = ctx->getNetinfoSourceWire(net);
if (src == WireId())
continue;
pool<WireId> sink_wires;
for (auto& usr : net->users)
for (auto sink_wire : ctx->getNetinfoSinkWires(net, usr))
sink_wires.insert(sink_wire);
did_something |= reserve_driver_wires_for_arc(net, sink_wires);
for (auto usr : net->users.enumerate())
did_something |= reserve_wires_for_arc(net, usr.index);
did_something |= reserve_sink_wires_for_arc(net, usr.index);
}
} while (did_something);
}