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Merge pull request #5023 from jix/restrict_share_activiation_patterns

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share: Restrict activation patterns to potentially relevant signals
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Jannis Harder 2025-04-16 16:33:34 +02:00 committed by GitHub
parent 04098933c7 4b273a4ae9
commit ecf9c9f0cf
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GPG key ID: B5690EEEBB952194
3 changed files with 121 additions and 23 deletions
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115
passes/opt/share.cc
View file

@ -1000,6 +1000,61 @@ struct ShareWorker
}
}
pool<std::pair<SigBit, State>> pattern_bits(const pool<ssc_pair_t> &activation_patterns)
{
pool<std::pair<SigBit, State>> bits;
for (auto const &pattern : activation_patterns) {
for (int i = 0; i < GetSize(pattern.second); ++i) {
SigBit bit = pattern.first[i];
State val = pattern.second[i];
bits.emplace(bit, val);
}
}
return bits;
}
bool onesided_restrict_activation_patterns(
pool<ssc_pair_t> &activation_patterns, const pool<std::pair<SigBit, State>> &other_bits)
{
pool<ssc_pair_t> new_activation_patterns;
bool simplified = false;
for (auto const &pattern : activation_patterns) {
ssc_pair_t new_pair;
for (int i = 0; i < GetSize(pattern.second); ++i) {
SigBit bit = pattern.first[i];
State val = pattern.second[i];
if (other_bits.count({bit, val == State::S0 ? State::S1 : State::S0})) {
new_pair.first.append(bit);
new_pair.second.append(val);
} else {
simplified = true;
}
}
new_activation_patterns.emplace(std::move(new_pair));
}
activation_patterns = std::move(new_activation_patterns);
return simplified;
}
// Only valid if the patterns on their own (i.e. without considering their input cone) are mutually exclusive!
bool restrict_activation_patterns(pool<ssc_pair_t> &activation_patterns, pool<ssc_pair_t> &other_activation_patterns)
{
pool<std::pair<SigBit, State>> bits = pattern_bits(activation_patterns);
pool<std::pair<SigBit, State>> other_bits = pattern_bits(other_activation_patterns);
bool simplified = false;
simplified |= onesided_restrict_activation_patterns(activation_patterns, other_bits);
simplified |= onesided_restrict_activation_patterns(other_activation_patterns, bits);
optimize_activation_patterns(activation_patterns);
optimize_activation_patterns(other_activation_patterns);
return simplified;
}
RTLIL::SigSpec make_cell_activation_logic(const pool<ssc_pair_t> &activation_patterns, pool<RTLIL::Cell*> &supercell_aux)
{
RTLIL::Wire *all_cases_wire = module->addWire(NEW_ID, 0);
@ -1299,17 +1354,18 @@ struct ShareWorker
other_cell_active.push_back(qcsat.ez->vec_eq(qcsat.importSig(p.first), qcsat.importSig(p.second)));
all_ctrl_signals.append(p.first);
}
int sub1 = qcsat.ez->expression(qcsat.ez->OpOr, cell_active);
int sub2 = qcsat.ez->expression(qcsat.ez->OpOr, other_cell_active);
bool pattern_only_solve = qcsat.ez->solve(qcsat.ez->AND(sub1, sub2));
qcsat.prepare();
int sub1 = qcsat.ez->expression(qcsat.ez->OpOr, cell_active);
if (!qcsat.ez->solve(sub1)) {
log(" According to the SAT solver the cell %s is never active. Sharing is pointless, we simply remove it.\n", log_id(cell));
cells_to_remove.insert(cell);
break;
}
int sub2 = qcsat.ez->expression(qcsat.ez->OpOr, other_cell_active);
if (!qcsat.ez->solve(sub2)) {
log(" According to the SAT solver the cell %s is never active. Sharing is pointless, we simply remove it.\n", log_id(other_cell));
cells_to_remove.insert(other_cell);
@ -1317,28 +1373,43 @@ struct ShareWorker
continue;
}
qcsat.ez->non_incremental();
pool<ssc_pair_t> optimized_cell_activation_patterns = filtered_cell_activation_patterns;
pool<ssc_pair_t> optimized_other_cell_activation_patterns = filtered_other_cell_activation_patterns;
all_ctrl_signals.sort_and_unify();
std::vector<int> sat_model = qcsat.importSig(all_ctrl_signals);
std::vector<bool> sat_model_values;
if (pattern_only_solve) {
qcsat.ez->non_incremental();
qcsat.ez->assume(qcsat.ez->AND(sub1, sub2));
all_ctrl_signals.sort_and_unify();
std::vector<int> sat_model = qcsat.importSig(all_ctrl_signals);
std::vector<bool> sat_model_values;
log(" Size of SAT problem: %zu cells, %d variables, %d clauses\n",
qcsat.imported_cells.size(), qcsat.ez->numCnfVariables(), qcsat.ez->numCnfClauses());
qcsat.ez->assume(qcsat.ez->AND(sub1, sub2));
if (qcsat.ez->solve(sat_model, sat_model_values)) {
log(" According to the SAT solver this pair of cells can not be shared.\n");
log(" Model from SAT solver: %s = %d'", log_signal(all_ctrl_signals), GetSize(sat_model_values));
for (int i = GetSize(sat_model_values)-1; i >= 0; i--)
log("%c", sat_model_values[i] ? '1' : '0');
log("\n");
continue;
log(" Size of SAT problem: %zu cells, %d variables, %d clauses\n",
qcsat.imported_cells.size(), qcsat.ez->numCnfVariables(), qcsat.ez->numCnfClauses());
if (qcsat.ez->solve(sat_model, sat_model_values)) {
log(" According to the SAT solver this pair of cells can not be shared.\n");
log(" Model from SAT solver: %s = %d'", log_signal(all_ctrl_signals), GetSize(sat_model_values));
for (int i = GetSize(sat_model_values)-1; i >= 0; i--)
log("%c", sat_model_values[i] ? '1' : '0');
log("\n");
continue;
}
log(" According to the SAT solver this pair of cells can be shared.\n");
} else {
log(" According to the SAT solver this pair of cells can be shared. (Pattern only case)\n");
if (restrict_activation_patterns(optimized_cell_activation_patterns, optimized_other_cell_activation_patterns)) {
for (auto &p : optimized_cell_activation_patterns)
log(" Simplified activation pattern for cell %s: %s = %s\n", log_id(cell), log_signal(p.first), log_signal(p.second));
for (auto &p : optimized_other_cell_activation_patterns)
log(" Simplified activation pattern for cell %s: %s = %s\n", log_id(other_cell), log_signal(p.first), log_signal(p.second));
}
}
log(" According to the SAT solver this pair of cells can be shared.\n");
if (find_in_input_cone(cell, other_cell)) {
log(" Sharing not possible: %s is in input cone of %s.\n", log_id(other_cell), log_id(cell));
continue;
@ -1354,20 +1425,20 @@ struct ShareWorker
int cell_select_score = 0;
int other_cell_select_score = 0;
for (auto &p : filtered_cell_activation_patterns)
for (auto &p : optimized_cell_activation_patterns)
cell_select_score += p.first.size();
for (auto &p : filtered_other_cell_activation_patterns)
for (auto &p : optimized_other_cell_activation_patterns)
other_cell_select_score += p.first.size();
RTLIL::Cell *supercell;
pool<RTLIL::Cell*> supercell_aux;
if (cell_select_score <= other_cell_select_score) {
RTLIL::SigSpec act = make_cell_activation_logic(filtered_cell_activation_patterns, supercell_aux);
RTLIL::SigSpec act = make_cell_activation_logic(optimized_cell_activation_patterns, supercell_aux);
supercell = make_supercell(cell, other_cell, act, supercell_aux);
log(" Activation signal for %s: %s\n", log_id(cell), log_signal(act));
} else {
RTLIL::SigSpec act = make_cell_activation_logic(filtered_other_cell_activation_patterns, supercell_aux);
RTLIL::SigSpec act = make_cell_activation_logic(optimized_other_cell_activation_patterns, supercell_aux);
supercell = make_supercell(other_cell, cell, act, supercell_aux);
log(" Activation signal for %s: %s\n", log_id(other_cell), log_signal(act));
}

23
tests/sat/share.v
View file

@ -30,3 +30,26 @@ module test_2(
end
endmodule
module test_3(
input [3:0] s,
input [7:0] a, b, c,
output reg [7:0] y0,
output reg [7:0] y1,
output reg [7:0] y2,
output reg [7:0] y3,
);
wire is_onehot = s & (s - 1);
always @* begin
y0 <= 0;
y1 <= 0;
y2 <= 0;
y3 <= 0;
if (s < 3) y0 <= b / c;
if (3 <= s && s < 6) y1 <= c / b;
if (6 <= s && s < 9) y2 <= a / b;
if (9 <= s && s < 12) y3 <= b / a;
end
endmodule

6
tests/sat/share.ys
View file

@ -3,11 +3,13 @@ proc;;
copy test_1 gold_1
copy test_2 gold_2
share test_1 test_2;;
copy test_3 gold_3
share test_1 test_2 test_3;;
select -assert-count 1 test_1/t:$mul
select -assert-count 1 test_2/t:$mul
select -assert-count 1 test_2/t:$div
select -assert-count 1 test_3/t:$div
miter -equiv -flatten -make_outputs -make_outcmp gold_1 test_1 miter_1
sat -verify -prove trigger 0 -show-inputs -show-outputs miter_1
@ -15,3 +17,5 @@ sat -verify -prove trigger 0 -show-inputs -show-outputs miter_1
miter -equiv -flatten -make_outputs -make_outcmp gold_2 test_2 miter_2
sat -verify -prove trigger 0 -show-inputs -show-outputs miter_2
miter -equiv -flatten -make_outputs -make_outcmp gold_3 test_3 miter_3
sat -verify -prove trigger 0 -show-inputs -show-outputs miter_3