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opt_dff minor cleanup, added tests for comp var.

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This commit is contained in:
nella 2026-01-26 14:24:01 +01:00
parent 0e4282d442
commit a75e0b2e92
3 changed files with 215 additions and 15 deletions
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20
passes/opt/opt_dff.cc
View file

@ -27,6 +27,7 @@
#include "kernel/ffinit.h"
#include "kernel/ff.h"
#include "passes/techmap/simplemap.h"
#include "passes/opt/opt_dff_comp.h"
#include <stdio.h>
#include <stdlib.h>
@ -55,7 +56,7 @@ struct OptDffWorker
dict<SigBit, int> bitusers; // Signal sink count
dict<SigBit, cell_int_t> bit2mux; // Signal bit to driving MUX
// Eattern matching for clock enable
// Pattern matching for clock enable
typedef std::map<RTLIL::SigBit, bool> pattern_t; // Control signal -> required vals
typedef std::set<pattern_t> patterns_t; // Alternative patterns (OR)
typedef std::pair<RTLIL::SigBit, bool> ctrl_t; // Control signal
@ -224,17 +225,6 @@ struct OptDffWorker
{
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 {};
if (right.at(pt.first) == pt.second) continue;
if (ret) return {};
ret = pt.first;
}
return ret;
};
// Remove complimentary patterns
bool optimized;
do {
@ -243,7 +233,7 @@ struct OptDffWorker
for (auto j = std::next(i, 1); j != patterns.end(); j++) {
const auto& left = (GetSize(*j) <= GetSize(*i)) ? *j : *i;
auto right = (GetSize(*i) < GetSize(*j)) ? *j : *i;
const auto complimentary_var = find_comp(left, right);
const auto complimentary_var = find_complementary_pattern_var(left, right);
if (complimentary_var && new_patterns.count(right)) {
new_patterns.erase(right);
@ -624,7 +614,7 @@ struct OptDffWorker
ctrls_t resets;
State reset_val = ff.has_srst ? ff.val_srst[i] : State::Sx;
while (bit2mux.count(ff.sig_d[i]) && bitusers[ff.sig_d[i]] == 1) {
if (bit2mux.count(ff.sig_d[i]) && bitusers[ff.sig_d[i]] == 1) {
cell_int_t mbit = bit2mux.at(ff.sig_d[i]);
if (GetSize(mbit.first->getPort(ID::S)) != 1)
break;
@ -712,7 +702,7 @@ struct OptDffWorker
for (int i = 0; i < ff.width; i++) {
ctrls_t enables;
while (bit2mux.count(ff.sig_d[i]) && bitusers[ff.sig_d[i]] == 1) {
if (bit2mux.count(ff.sig_d[i]) && bitusers[ff.sig_d[i]] == 1) {
cell_int_t mbit = bit2mux.at(ff.sig_d[i]);
if (GetSize(mbit.first->getPort(ID::S)) != 1)
break;

31
passes/opt/opt_dff_comp.h Normal file
View file

@ -0,0 +1,31 @@
#ifndef OPT_DFF_COMP_H
#define OPT_DFF_COMP_H
#include "kernel/rtlil.h"
#include <map>
#include <optional>
YOSYS_NAMESPACE_BEGIN
typedef std::map<RTLIL::SigBit, bool> pattern_t;
inline std::optional<RTLIL::SigBit> find_complementary_pattern_var(
const pattern_t& left,
const pattern_t& right
) {
std::optional<RTLIL::SigBit> ret;
for (const auto &pt : left) {
if (right.count(pt.first) == 0)
return std::nullopt;
if (right.at(pt.first) == pt.second)
continue;
if (ret)
return std::nullopt;
ret = pt.first;
}
return ret;
}
YOSYS_NAMESPACE_END
#endif