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-rw-r--r--passes/opt/opt_const.cc121
1 files changed, 115 insertions, 6 deletions
diff --git a/passes/opt/opt_const.cc b/passes/opt/opt_const.cc
index 76948344..a17ca679 100644
--- a/passes/opt/opt_const.cc
+++ b/passes/opt/opt_const.cc
@@ -25,11 +25,11 @@
#include <stdlib.h>
#include <assert.h>
#include <stdio.h>
-#include <set>
+#include <algorithm>
static bool did_something;
-void replace_undriven(RTLIL::Design *design, RTLIL::Module *module)
+static void replace_undriven(RTLIL::Design *design, RTLIL::Module *module)
{
CellTypes ct(design);
SigMap sigmap(module);
@@ -71,7 +71,7 @@ void replace_undriven(RTLIL::Design *design, RTLIL::Module *module)
}
}
-void replace_cell(RTLIL::Module *module, RTLIL::Cell *cell, std::string info, std::string out_port, RTLIL::SigSpec out_val)
+static void replace_cell(RTLIL::Module *module, RTLIL::Cell *cell, std::string info, std::string out_port, RTLIL::SigSpec out_val)
{
RTLIL::SigSpec Y = cell->connections[out_port];
log("Replacing %s cell `%s' (%s) in module `%s' with constant driver `%s = %s'.\n",
@@ -85,7 +85,103 @@ void replace_cell(RTLIL::Module *module, RTLIL::Cell *cell, std::string info, st
did_something = true;
}
-void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool consume_x, bool mux_undef, bool mux_bool)
+static bool group_cell_inputs(RTLIL::Module *module, RTLIL::Cell *cell, bool commutative, bool extend_u0, SigMap &sigmap)
+{
+ std::string b_name = cell->connections.count("\\B") ? "\\B" : "\\A";
+
+ bool a_signed = cell->parameters.at("\\A_SIGNED").as_bool();
+ bool b_signed = cell->parameters.at(b_name + "_SIGNED").as_bool();
+
+ RTLIL::SigSpec sig_a = sigmap(cell->connections.at("\\A"));
+ RTLIL::SigSpec sig_b = sigmap(cell->connections.at(b_name));
+ RTLIL::SigSpec sig_y = sigmap(cell->connections.at("\\Y"));
+
+ if (extend_u0) {
+ sig_a.extend_u0(sig_y.width, a_signed);
+ sig_b.extend_u0(sig_y.width, b_signed);
+ } else {
+ sig_a.extend(sig_y.width, a_signed);
+ sig_b.extend(sig_y.width, b_signed);
+ }
+
+ std::vector<RTLIL::SigBit> bits_a = sig_a, bits_b = sig_b, bits_y = sig_y;
+
+ enum { GRP_DYN, GRP_CONST_A, GRP_CONST_B, GRP_CONST_AB, GRP_N };
+ std::map<std::pair<RTLIL::SigBit, RTLIL::SigBit>, std::set<RTLIL::SigBit>> grouped_bits[GRP_N];
+
+ for (int i = 0; i < SIZE(bits_y); i++)
+ {
+ int group_idx = GRP_DYN;
+ RTLIL::SigBit bit_a = bits_a[i], bit_b = bits_b[i];
+
+ if (bit_a.wire == NULL && bit_b.wire == NULL)
+ group_idx = GRP_CONST_AB;
+ else if (bit_a.wire == NULL)
+ group_idx = GRP_CONST_A;
+ else if (bit_b.wire == NULL && commutative)
+ group_idx = GRP_CONST_A, std::swap(bit_a, bit_b);
+ else if (bit_b.wire == NULL)
+ group_idx = GRP_CONST_B;
+
+ grouped_bits[group_idx][std::pair<RTLIL::SigBit, RTLIL::SigBit>(bit_a, bit_b)].insert(bits_y[i]);
+ }
+
+ for (int i = 0; i < GRP_N; i++)
+ if (SIZE(grouped_bits[i]) == SIZE(bits_y))
+ return false;
+
+ log("Replacing %s cell `%s' in module `%s' with cells using grouped bits:\n",
+ log_id(cell->type), log_id(cell), log_id(module));
+
+ for (int i = 0; i < GRP_N; i++)
+ {
+ if (grouped_bits[i].empty())
+ continue;
+
+ RTLIL::Wire *new_y = module->addWire(NEW_ID, SIZE(grouped_bits[i]));
+ RTLIL::SigSpec new_a, new_b;
+ RTLIL::SigSig new_conn;
+
+ for (auto &it : grouped_bits[i]) {
+ for (auto &bit : it.second) {
+ new_conn.first.append_bit(bit);
+ new_conn.second.append_bit(RTLIL::SigBit(new_y, new_a.width));
+ }
+ new_a.append_bit(it.first.first);
+ new_b.append_bit(it.first.second);
+ }
+
+ RTLIL::Cell *c = module->addCell(NEW_ID, cell->type);
+
+ c->connections["\\A"] = new_a;
+ c->parameters["\\A_WIDTH"] = new_a.width;
+ c->parameters["\\A_SIGNED"] = false;
+
+ if (b_name == "\\B") {
+ c->connections["\\B"] = new_b;
+ c->parameters["\\B_WIDTH"] = new_b.width;
+ c->parameters["\\B_SIGNED"] = false;
+ }
+
+ c->connections["\\Y"] = new_y;
+ c->parameters["\\Y_WIDTH"] = new_y->width;
+ c->check();
+
+ module->connections.push_back(new_conn);
+
+ log(" New cell `%s': A=%s", log_id(c), log_signal(new_a));
+ if (b_name == "\\B")
+ log(", B=%s", log_signal(new_b));
+ log("\n");
+ }
+
+ module->remove(cell);
+ OPT_DID_SOMETHING = true;
+ did_something = true;
+ return true;
+}
+
+static void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool consume_x, bool mux_undef, bool mux_bool, bool do_fine)
{
if (!design->selected(module))
return;
@@ -108,6 +204,11 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool cons
#define ACTION_DO(_p_, _s_) do { replace_cell(module, cell, input.as_string(), _p_, _s_); goto next_cell; } while (0)
#define ACTION_DO_Y(_v_) ACTION_DO("\\Y", RTLIL::SigSpec(RTLIL::State::S ## _v_))
+ if (do_fine && (cell->type == "$not" || cell->type == "$pos" || cell->type == "$bu0" ||
+ cell->type == "$and" || cell->type == "$or" || cell->type == "$xor" || cell->type == "$xnor"))
+ if (group_cell_inputs(module, cell, true, cell->type != "$pos", assign_map))
+ goto next_cell;
+
if ((cell->type == "$_INV_" || cell->type == "$not" || cell->type == "$logic_not") && cell->connections["\\Y"].width == 1 &&
invert_map.count(assign_map(cell->connections["\\A"])) != 0) {
replace_cell(module, cell, "double_invert", "\\Y", invert_map.at(assign_map(cell->connections["\\A"])));
@@ -573,12 +674,16 @@ struct OptConstPass : public Pass {
log(" -undriven\n");
log(" replace undriven nets with undef (x) constants\n");
log("\n");
+ log(" -fine\n");
+ log(" perform fine-grain optimizations\n");
+ log("\n");
}
virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
{
bool mux_undef = false;
bool mux_bool = false;
bool undriven = false;
+ bool do_fine = false;
log_header("Executing OPT_CONST pass (perform const folding).\n");
log_push();
@@ -597,6 +702,10 @@ struct OptConstPass : public Pass {
undriven = true;
continue;
}
+ if (args[argidx] == "-fine") {
+ do_fine = true;
+ continue;
+ }
break;
}
extra_args(args, argidx, design);
@@ -609,9 +718,9 @@ struct OptConstPass : public Pass {
do {
do {
did_something = false;
- replace_const_cells(design, mod_it.second, false, mux_undef, mux_bool);
+ replace_const_cells(design, mod_it.second, false, mux_undef, mux_bool, do_fine);
} while (did_something);
- replace_const_cells(design, mod_it.second, true, mux_undef, mux_bool);
+ replace_const_cells(design, mod_it.second, true, mux_undef, mux_bool, do_fine);
} while (did_something);
}