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-rw-r--r--passes/sat/equiv_simple.cc144
1 files changed, 105 insertions, 39 deletions
diff --git a/passes/sat/equiv_simple.cc b/passes/sat/equiv_simple.cc
index ffc1e3f5b..b87f4ed70 100644
--- a/passes/sat/equiv_simple.cc
+++ b/passes/sat/equiv_simple.cc
@@ -33,14 +33,15 @@ struct EquivSimpleWorker
ezDefaultSAT ez;
SatGen satgen;
+ int max_seq;
- EquivSimpleWorker(Cell *equiv_cell, SigMap &sigmap, dict<SigBit, Cell*> &bit2driver) :
+ EquivSimpleWorker(Cell *equiv_cell, SigMap &sigmap, dict<SigBit, Cell*> &bit2driver, int max_seq) :
module(equiv_cell->module), equiv_cell(equiv_cell), sigmap(sigmap),
- bit2driver(bit2driver), satgen(&ez, &sigmap)
+ bit2driver(bit2driver), satgen(&ez, &sigmap), max_seq(max_seq)
{
}
- void find_input_cone(pool<Cell*> &cells_cone, pool<SigBit> &bits_cone, const pool<Cell*> &cells_stop, const pool<SigBit> &bits_stop, Cell *cell)
+ void find_input_cone(pool<SigBit> &next_seed, pool<Cell*> &cells_cone, pool<SigBit> &bits_cone, const pool<Cell*> &cells_stop, const pool<SigBit> &bits_stop, Cell *cell)
{
if (cells_cone.count(cell))
return;
@@ -52,11 +53,16 @@ struct EquivSimpleWorker
for (auto &conn : cell->connections())
if (yosys_celltypes.cell_input(cell->type, conn.first))
- for (auto bit : sigmap(conn.second))
- find_input_cone(cells_cone, bits_cone, cells_stop, bits_stop, bit);
+ for (auto bit : sigmap(conn.second)) {
+ if (cell->type.in("$dff", "$_DFF_P_", "$_DFF_N_")) {
+ if (!conn.first.in("\\CLK", "\\C"))
+ next_seed.insert(bit);
+ } else
+ find_input_cone(next_seed, cells_cone, bits_cone, cells_stop, bits_stop, bit);
+ }
}
- void find_input_cone(pool<Cell*> &cells_cone, pool<SigBit> &bits_cone, const pool<Cell*> &cells_stop, const pool<SigBit> &bits_stop, SigBit bit)
+ void find_input_cone(pool<SigBit> &next_seed, pool<Cell*> &cells_cone, pool<SigBit> &bits_cone, const pool<Cell*> &cells_stop, const pool<SigBit> &bits_stop, SigBit bit)
{
if (bits_cone.count(bit))
return;
@@ -69,7 +75,7 @@ struct EquivSimpleWorker
if (!bit2driver.count(bit))
return;
- find_input_cone(cells_cone, bits_cone, cells_stop, bits_stop, bit2driver.at(bit));
+ find_input_cone(next_seed, cells_cone, bits_cone, cells_stop, bits_stop, bit2driver.at(bit));
}
bool run()
@@ -77,42 +83,98 @@ struct EquivSimpleWorker
SigBit bit_a = sigmap(equiv_cell->getPort("\\A")).to_single_sigbit();
SigBit bit_b = sigmap(equiv_cell->getPort("\\B")).to_single_sigbit();
+ int ez_a = satgen.importSigBit(bit_a, max_seq+1);
+ int ez_b = satgen.importSigBit(bit_b, max_seq+1);
+ ez.assume(ez.XOR(ez_a, ez_b));
+
+ pool<SigBit> seed_a = { bit_a };
+ pool<SigBit> seed_b = { bit_b };
+
log(" Trying to prove $equiv cell %s:\n", log_id(equiv_cell));
log(" A = %s, B = %s, Y = %s\n", log_signal(bit_a), log_signal(bit_b), log_signal(equiv_cell->getPort("\\Y")));
- pool<Cell*> no_stop_cells;
- pool<SigBit> no_stop_bits;
+ int step = max_seq;
+ while (1)
+ {
+ pool<Cell*> no_stop_cells;
+ pool<SigBit> no_stop_bits;
- pool<Cell*> full_cells_cone_a, full_cells_cone_b;
- pool<SigBit> full_bits_cone_a, full_bits_cone_b;
+ pool<Cell*> full_cells_cone_a, full_cells_cone_b;
+ pool<SigBit> full_bits_cone_a, full_bits_cone_b;
- find_input_cone(full_cells_cone_a, full_bits_cone_a, no_stop_cells, no_stop_bits, bit_a);
- find_input_cone(full_cells_cone_b, full_bits_cone_b, no_stop_cells, no_stop_bits, bit_b);
+ pool<SigBit> next_seed_a, next_seed_b;
- pool<Cell*> short_cells_cone_a, short_cells_cone_b;
- pool<SigBit> short_bits_cone_a, short_bits_cone_b;
+ for (auto bit_a : seed_a)
+ find_input_cone(next_seed_a, full_cells_cone_a, full_bits_cone_a, no_stop_cells, no_stop_bits, bit_a);
+ next_seed_a.clear();
- find_input_cone(short_cells_cone_a, short_bits_cone_a, full_cells_cone_b, full_bits_cone_b, bit_a);
- find_input_cone(short_cells_cone_b, short_bits_cone_b, full_cells_cone_a, full_bits_cone_a, bit_b);
+ for (auto bit_b : seed_b)
+ find_input_cone(next_seed_b, full_cells_cone_b, full_bits_cone_b, no_stop_cells, no_stop_bits, bit_b);
+ next_seed_b.clear();
- pool<Cell*> problem_cells;
- problem_cells.insert(short_cells_cone_a.begin(), short_cells_cone_a.end());
- problem_cells.insert(short_cells_cone_b.begin(), short_cells_cone_b.end());
- for (auto cell : problem_cells) satgen.importCell(cell);
+ pool<Cell*> short_cells_cone_a, short_cells_cone_b;
+ pool<SigBit> short_bits_cone_a, short_bits_cone_b;
- int ez_a = satgen.importSigBit(bit_a);
- int ez_b = satgen.importSigBit(bit_b);
- ez.assume(ez.XOR(ez_a, ez_b));
+ for (auto bit_a : seed_a)
+ find_input_cone(next_seed_a, short_cells_cone_a, short_bits_cone_a, full_cells_cone_b, full_bits_cone_b, bit_a);
+ next_seed_a.swap(seed_a);
+
+ for (auto bit_b : seed_b)
+ find_input_cone(next_seed_b, short_cells_cone_b, short_bits_cone_b, full_cells_cone_a, full_bits_cone_a, bit_b);
+ next_seed_b.swap(seed_b);
+
+ pool<Cell*> problem_cells;
+ problem_cells.insert(short_cells_cone_a.begin(), short_cells_cone_a.end());
+ problem_cells.insert(short_cells_cone_b.begin(), short_cells_cone_b.end());
+
+ log(" Adding %d new cells to the problem (%d A, %d B, %d shared).\n",
+ GetSize(problem_cells), GetSize(short_cells_cone_a), GetSize(short_cells_cone_b),
+ (GetSize(short_cells_cone_a) + GetSize(short_cells_cone_b)) - GetSize(problem_cells));
+
+ for (auto cell : problem_cells)
+ satgen.importCell(cell, step+1);
+
+ log(" Problem size at t=%d: %d literals, %d clauses\n", step, ez.numCnfVariables(), ez.numCnfClauses());
+
+ if (!ez.solve()) {
+ log(" Proved equivalence! Marking $equiv cell as proven.\n");
+ equiv_cell->setPort("\\B", equiv_cell->getPort("\\A"));
+ return true;
+ }
- log(" Created SAT problem from %d cells.\n", GetSize(problem_cells));
+ log(" Failed to prove equivalence with sequence length %d.\n", max_seq - step);
- if (!ez.solve()) {
- log(" Proved equivalence! Marking $equiv cell as proven.\n");
- equiv_cell->setPort("\\B", equiv_cell->getPort("\\A"));
- return true;
+ if (--step < 0) {
+ log(" Reached sequence limit.\n");
+ break;
+ }
+
+ if (seed_a.empty() && seed_b.empty()) {
+ log(" No nets to continue in previous time step.\n");
+ break;
+ }
+
+ if (seed_a.empty()) {
+ log(" No nets on A-side to continue in previous time step.\n");
+ break;
+ }
+
+ if (seed_b.empty()) {
+ log(" No nets on B-side to continue in previous time step.\n");
+ break;
+ }
+
+ #if 0
+ log(" Continuing analysis in previous time step with the following nets:\n");
+ for (auto bit : seed_a)
+ log(" A: %s\n", log_signal(bit));
+ for (auto bit : seed_b)
+ log(" B: %s\n", log_signal(bit));
+ #else
+ log(" Continuing analysis in previous time step with %d A- and %d B-nets.\n", GetSize(seed_a), GetSize(seed_b));
+ #endif
}
- log(" Failed to prove equivalence.\n");
return false;
}
};
@@ -127,19 +189,23 @@ struct EquivSimplePass : public Pass {
log("\n");
log("This command tries to prove $equiv cells using a simple direct SAT approach.\n");
log("\n");
+ log(" -seq <N>\n");
+ log(" the max. number of time steps to be considered (default = 1)\n");
+ log("\n");
}
virtual void execute(std::vector<std::string> args, Design *design)
{
int success_counter = 0;
+ int max_seq = 1;
log_header("Executing EQUIV_SIMPLE pass.\n");
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++) {
- // if (args[argidx] == "-assert") {
- // assert_mode = true;
- // continue;
- // }
+ if (args[argidx] == "-seq" && argidx+1 < args.size()) {
+ max_seq = atoi(args[++argidx].c_str());
+ continue;
+ }
break;
}
extra_args(args, argidx, design);
@@ -164,23 +230,23 @@ struct EquivSimplePass : public Pass {
SigMap sigmap(module);
dict<SigBit, Cell*> bit2driver;
- for (auto cell : module->selected_cells()) {
- if (!ct.cell_known(cell->type))
+ for (auto cell : module->cells()) {
+ if (!ct.cell_known(cell->type) && !cell->type.in("$dff", "$_DFF_P_", "$_DFF_N_"))
continue;
for (auto &conn : cell->connections())
- if (ct.cell_output(cell->type, conn.first))
+ if (yosys_celltypes.cell_output(cell->type, conn.first))
for (auto bit : sigmap(conn.second))
bit2driver[bit] = cell;
}
for (auto cell : unproven_equiv_cells) {
- EquivSimpleWorker worker(cell, sigmap, bit2driver);
+ EquivSimpleWorker worker(cell, sigmap, bit2driver, max_seq);
if (worker.run())
success_counter++;
}
}
- log("Successfully proved %d previously unproven $equiv cells.\n", success_counter);
+ log("Proved %d previously unproven $equiv cells.\n", success_counter);
}
} EquivSimplePass;
generated by cgit v1.2.3 (git 2.25.1) at 2025-11-04 01:15:00 +0000