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opt_dff: implement simplify_patterns

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This commit is contained in:
Anhijkt 2025-07-21 14:15:26 +03:00
parent 3c5cc18a9f
commit ca8af1f8c8
2 changed files with 61 additions and 5 deletions
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60
passes/opt/opt_dff.cc
View file

@ -170,9 +170,65 @@ struct OptDffWorker
return ret;
}
void simplify_patterns(patterns_t&)
void simplify_patterns(patterns_t& patterns)
{
// TBD
// remove complimentary patterns
auto new_patterns = 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);
std::optional<RTLIL::SigBit> complimentary_var;
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);
bool redundant = true;
for (const auto& pt : left)
if (right.count(pt.first) == 0 || right[pt.first] != pt.second)
redundant = false;
if (redundant)
new_patterns.erase(right);
}
}
patterns = std::move(new_patterns)
}
ctrl_t make_patterns_logic(const patterns_t &patterns, const ctrls_t &ctrls, bool make_gates)

6
tests/arch/quicklogic/pp3/fsm.ys
View file

@ -11,8 +11,8 @@ sat -verify -prove-asserts -show-public -set-at 1 in_reset 1 -seq 20 -prove-skip
design -load postopt # load the post-opt design (otherwise equiv_opt loads the pre-opt design)
cd fsm # Constrain all select calls below inside the top module
select -assert-count 1 t:LUT2
select -assert-count 9 t:LUT3
select -assert-count 2 t:LUT2
select -assert-count 4 t:LUT3
select -assert-count 4 t:dffepc
select -assert-count 1 t:logic_0
select -assert-count 1 t:logic_1
@ -20,4 +20,4 @@ select -assert-count 3 t:inpad
select -assert-count 2 t:outpad
select -assert-count 1 t:ckpad
select -assert-none t:LUT2 t:LUT3 t:dffepc t:logic_0 t:logic_1 t:inpad t:outpad t:ckpad %% t:* %D
select -assert-none t:LUT2 t:LUT3 t:LUT4 t:dffepc t:logic_0 t:logic_1 t:inpad t:outpad t:ckpad %% t:* %D