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Add prepass for bit simulation.

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nella 2026-05-25 12:49:29 +02:00
parent 04a1611346
commit 386e63ae20
2 changed files with 142 additions and 1 deletions
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64
passes/opt/opt_dff.cc
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@ -26,6 +26,7 @@
#include "kernel/sigtools.h"
#include "kernel/ffinit.h"
#include "kernel/ff.h"
#include "kernel/bitsim.h"
#include "kernel/pattern.h"
#include "passes/techmap/simplemap.h"
#include <stdio.h>
@ -1067,6 +1068,67 @@ struct OptDffWorker
return false;
ModWalker modwalker(module->design, module);
BitSim sim(module, sigmap, modwalker);
// Simulation prepass
// Assume same class
for (auto &cls : classes) {
uint64_t class_q_val = sim.xorshift64();
for (int idx : cls) {
sim.sim_vals[sigmap(bits[idx].q)] = class_q_val;
}
}
std::vector<std::vector<int>> refined_classes;
for (auto &cls : classes) {
dict<uint64_t, std::vector<int>> sim_buckets;
for (int idx : cls) {
const EqBit &eb = bits[idx];
const FfData &ff = ff_for_cell.at(eb.cell);
uint64_t n_val = sim.eval_bit(ff.sig_d[eb.idx]);
if (ff.has_aload) {
uint64_t al = sim.eval_bit(ff.sig_aload);
if (!ff.pol_aload) al = ~al;
uint64_t ad = sim.eval_bit(ff.sig_ad[eb.idx]);
n_val = (n_val & ~al) | (ad & al);
}
if (ff.has_arst) {
uint64_t ar = sim.eval_bit(ff.sig_arst);
if (!ff.pol_arst) ar = ~ar;
uint64_t ar_val = (ff.val_arst[eb.idx] == State::S1) ? ~0ULL : 0ULL;
n_val = (n_val & ~ar) | (ar_val & ar);
}
if (ff.has_sr) {
uint64_t clr = sim.eval_bit(ff.sig_clr[eb.idx]);
if (!ff.pol_clr) clr = ~clr;
uint64_t set = sim.eval_bit(ff.sig_set[eb.idx]);
if (!ff.pol_set) set = ~set;
n_val = ~clr & (set | n_val);
}
if (ff.has_srst) {
uint64_t srst = sim.eval_bit(ff.sig_srst);
if (!ff.pol_srst) srst = ~srst;
uint64_t srst_val = (ff.val_srst[eb.idx] == State::S1) ? ~0ULL : 0ULL;
n_val = (n_val & ~srst) | (srst_val & srst);
}
sim_buckets[n_val].push_back(idx);
}
for (auto &kv : sim_buckets) {
if (GetSize(kv.second) >= 2) {
refined_classes.push_back(std::move(kv.second));
}
}
}
classes = std::move(refined_classes);
if (classes.empty())
return false;
QuickConeSat qcsat(modwalker);
std::vector<int> q_lit(bits.size(), -1);
std::vector<int> n_lit(bits.size(), -1);
@ -1136,7 +1198,7 @@ struct OptDffWorker
// Split at counterexamples
int rep = cls[0];
for (int i = 1; i < GetSize(cls); i++) {
// Trivially eqivalent
// Trivially equivalent
if (n_lit[rep] == n_lit[cls[i]])
continue;