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opt_dff: refactor simplify_patterns

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This commit is contained in:
Anhijkt 2025-07-30 21:31:34 +03:00
parent d9fc6dda9e
commit 206d2a4553
1 changed files with 25 additions and 28 deletions
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51
passes/opt/opt_dff.cc
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@ -172,60 +172,57 @@ struct OptDffWorker
void simplify_patterns(patterns_t& patterns)
{
// remove complimentary patterns
auto new_patterns = patterns;
auto find_comp = [](const auto& left, const auto& right) -> std::optional<RTLIL::SigBit> {
std::optional<RTLIL::SigBit> ret;
for (const auto &pt: left)
if (right.count(pt.first) == 0)
return {};
else if (right.at(pt.first) == pt.second)
continue;
else
if (ret)
return {};
else
ret = pt.first;
return ret;
};
// remove complimentary patterns
bool optimized;
do {
optimized = false;
for (auto i = patterns.begin(); i != patterns.end(); i++) {
for (auto j = std::next(i, 1); j != patterns.end(); j++) {
const auto& smaller = (GetSize(*j) <= GetSize(*i)) ? *j : *i;
const auto& larger = (GetSize(*i) < GetSize(*j)) ? *j : *i;
auto left = std::move(smaller);
auto right = std::move(larger);
const auto& left = (GetSize(*j) <= GetSize(*i)) ? *j : *i;
auto right = (GetSize(*i) < GetSize(*j)) ? *j : *i;
std::optional<RTLIL::SigBit> complimentary_var;
const auto complimentary_var = find_comp(left, right);
for (const auto &pt : left)
if (right.count(pt.first) == 0)
goto next;
else if (right[pt.first] == pt.second)
continue;
else
if (complimentary_var)
goto next;
else
complimentary_var = pt.first;
if (complimentary_var) {
new_patterns.erase(right);
right.erase(complimentary_var.value());
new_patterns.insert(right);
optimized = true;
}
next:
continue;
}
}
patterns = new_patterns;
} while(optimized);
// remove redundant patterns
for (auto i = patterns.begin(); i != patterns.end(); ++i) {
for (auto j = std::next(i, 1); j != patterns.end(); ++j) {
const auto& smaller = (GetSize(*j) <= GetSize(*i)) ? *j : *i;
const auto& larger = (GetSize(*i) < GetSize(*j)) ? *j : *i;
auto left = std::move(smaller);
auto right = std::move(larger);
const auto& left = (GetSize(*j) <= GetSize(*i)) ? *j : *i;
const auto& right = (GetSize(*i) < GetSize(*j)) ? *j : *i;
bool redundant = true;
for (const auto& pt : left)
if (right.count(pt.first) == 0 || right[pt.first] != pt.second)
for (const auto& pt : smaller)
if (larger.count(pt.first) == 0 || larger[pt.first] != pt.second)
redundant = false;
if (redundant)
new_patterns.erase(right);
new_patterns.erase(larger);
}
}
patterns = std::move(new_patterns);