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Merge pull request #1085 from YosysHQ/eddie/shregmap_improve

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Improve shregmap to handle case where first flop is common to two chains
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Eddie Hung 2019-06-21 08:56:56 -07:00 • committed by GitHub
commit 6d74cf0d2b
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3 changed files with 129 additions and 3 deletions
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18
passes/techmap/shregmap.cc
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@ -293,10 +293,22 @@ struct ShregmapWorker
if (opts.init || sigbit_init.count(q_bit) == 0)
{
if (sigbit_chain_next.count(d_bit)) {
auto r = sigbit_chain_next.insert(std::make_pair(d_bit, cell));
if (!r.second) {
// Insertion not successful means that d_bit is already
// connected to another register, thus mark it as a
// non chain user ...
sigbit_with_non_chain_users.insert(d_bit);
} else
sigbit_chain_next[d_bit] = cell;
// ... and clone d_bit into another wire, and use that
// wire as a different key in the d_bit-to-cell dictionary
// so that it can be identified as another chain
// (omitting this common flop)
// Link: https://github.com/YosysHQ/yosys/pull/1085
Wire *wire = module->addWire(NEW_ID);
module->connect(wire, d_bit);
sigmap.add(wire, d_bit);
sigbit_chain_next.insert(std::make_pair(wire, cell));
}
sigbit_chain_prev[q_bit] = cell;
continue;