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| author | David Shah <dave@ds0.me> | 2019-11-20 15:13:28 +0000 |
|---|---|---|
| committer | David Shah <dave@ds0.me> | 2020-02-03 11:38:31 +0000 |
| commit | 59c554b50ad599cbfc6f832b6942075efe3a0dbe (patch) | |
| tree | 0a1ed62fc469a35c43aeea7fca1f12bdd2ba9e8d | |
| parent | 363d664f273976e1d1e23bd272329dbff3c858ce (diff) | |
| download | nextpnr-59c554b50ad599cbfc6f832b6942075efe3a0dbe.tar.gz nextpnr-59c554b50ad599cbfc6f832b6942075efe3a0dbe.tar.bz2 nextpnr-59c554b50ad599cbfc6f832b6942075efe3a0dbe.zip | |
router2: Improve backwards routing of some cases
Signed-off-by: David Shah <dave@ds0.me>
| -rw-r--r-- | common/router2.cc | 28 |
1 files changed, 27 insertions, 1 deletions
diff --git a/common/router2.cc b/common/router2.cc index fcd52bb3..271595ad 100644 --- a/common/router2.cc +++ b/common/router2.cc @@ -374,8 +374,34 @@ struct Router2 t.backwards_queue.pop(); auto &cwd = wires.at(cursor); PipId cpip; - if (cwd.bound_nets.count(net->udata)) + if (cwd.bound_nets.count(net->udata)) { + // If we can tack onto existing routing; try that + // Only do this if the existing routing is uncontented; however + WireId cursor2 = cursor; + bool bwd_merge_fail = false; + while (wires.at(cursor2).bound_nets.count(net->udata)) { + if (wires.at(cursor2).bound_nets.size() > 1) { + bwd_merge_fail = true; + break; + } + PipId p = wires.at(cursor2).bound_nets.at(net->udata).second; + if (p == PipId()) + break; + cursor2 = ctx->getPipSrcWire(p); + } + if (!bwd_merge_fail && cursor2 == src_wire) { + // Found a path to merge to existing routing; backwards + cursor2 = cursor; + while (wires.at(cursor2).bound_nets.count(net->udata)) { + PipId p = wires.at(cursor2).bound_nets.at(net->udata).second; + if (p == PipId()) + break; + cursor2 = ctx->getPipSrcWire(p); + t.backwards_pip[cursor2] = p; + } + } cpip = cwd.bound_nets.at(net->udata).second; + } bool did_something = false; for (auto uh : ctx->getPipsUphill(cursor)) { did_something = true; |