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Merge 97d3f07e78 into ac96f318ef

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Arnim Läuger 2026-02-13 17:23:09 +01:00 • committed by GitHub
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64
passes/opt/opt_dff.cc
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@ -919,6 +919,68 @@ struct OptDffWorker
return did_something;
}
bool run_related_load_data() {
ModWalker modwalker(module->design, module);
QuickConeSat qcsat(modwalker);
// Defer mutating cells by emiting new flip flops so that
// cell references in modwalker are not invalidated
std::vector<FfData> ffs_to_emit;
bool did_something = false;
for (auto cell : module->selected_cells()) {
if (!cell->is_builtin_ff())
continue;
FfData ff(&initvals, cell);
if (ff.has_aload) {
if (!ff.sig_aload[0].wire)
continue;
bool changed_ff = false;
for (int i = 0; i < ff.width; i++) {
if (!ff.sig_ad[i].wire) {
// Nothing to do
continue;
}
// Change AD to const if it's identical or complementary to ALOAD.
if (ff.sig_aload == ff.sig_ad[i]) {
log("Changing same-signal async load to constant at position %d on %s (%s) from module %s.\n",
i, log_id(cell), log_id(cell->type), log_id(module));
ff.sig_ad[i] = ff.pol_aload ? State::S1 : State::S0;
changed_ff = true;
} else {
if (!opt.sat)
continue;
int aload_pol_sat_pi = qcsat.importSigBit(ff.pol_aload ? State::S1 : State::S0);
int aload_not_pol_sat_pi = qcsat.importSigBit(ff.pol_aload ? State::S0 : State::S1);
int aload_sat_pi = qcsat.importSigBit(ff.sig_aload);
int ad_sat_pi = qcsat.importSigBit(ff.sig_ad[i]);
qcsat.prepare();
if (!qcsat.ez->solve(qcsat.ez->IFF(aload_sat_pi, aload_pol_sat_pi), qcsat.ez->NOT(qcsat.ez->IFF(ad_sat_pi, aload_not_pol_sat_pi)))) {
log("Changing comp-signal async load to constant at position %d on %s (%s) from module %s.\n",
i, log_id(cell), log_id(cell->type), log_id(module));
ff.sig_ad[i] = ff.pol_aload ? State::S0 : State::S1;
changed_ff = true;
}
}
}
if (changed_ff) {
ffs_to_emit.emplace_back(ff);
did_something = true;
}
}
}
for (auto& ff : ffs_to_emit)
ff.emit();
return did_something;
}
};
struct OptDffPass : public Pass {
@ -985,6 +1047,8 @@ struct OptDffPass : public Pass {
OptDffWorker worker(opt, mod);
if (worker.run())
did_something = true;
if (worker.run_related_load_data())
did_something = true;
if (worker.run_constbits())
did_something = true;
}