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Added "opt_const -mux_undef"

This commit is contained in:
Clifford Wolf 2014-01-14 11:10:29 +01:00
parent a3d94bf888
commit 54275c61ee
1 changed files with 71 additions and 5 deletions
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76
passes/opt/opt_const.cc
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@ -42,7 +42,7 @@ 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)
void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool consume_x, bool mux_undef)
{
if (!design->selected(module))
return;
@ -139,8 +139,16 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool cons
cell->connections.erase("\\S");
goto next_cell;
}
if (input.match("11 ")) ACTION_DO_Y(1);
if (input.match("00 ")) ACTION_DO_Y(0);
if (input.match("** ")) ACTION_DO_Y(x);
if (input.match("01*")) ACTION_DO_Y(x);
if (input.match("10*")) ACTION_DO_Y(x);
if (mux_undef) {
if (input.match("* ")) ACTION_DO("\\Y", input.extract(1, 1));
if (input.match(" * ")) ACTION_DO("\\Y", input.extract(2, 1));
if (input.match(" *")) ACTION_DO("\\Y", input.extract(2, 1));
}
}
if (cell->type == "$eq" || cell->type == "$ne" || cell->type == "$eqx" || cell->type == "$nex")
@ -216,6 +224,51 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool cons
}
}
if (mux_undef && (cell->type == "$mux" || cell->type == "$pmux")) {
RTLIL::SigSpec new_a, new_b, new_s;
int width = cell->connections.at("\\A").width;
if ((cell->connections.at("\\A").is_fully_undef() && cell->connections.at("\\B").is_fully_undef()) ||
cell->connections.at("\\S").is_fully_undef()) {
replace_cell(module, cell, "mux undef", "\\Y", cell->connections.at("\\A"));
goto next_cell;
}
for (int i = 0; i < cell->connections.at("\\S").width; i++) {
RTLIL::SigSpec old_b = cell->connections.at("\\B").extract(i*width, width);
RTLIL::SigSpec old_s = cell->connections.at("\\S").extract(i, 1);
if (old_b.is_fully_undef() || old_s.is_fully_undef())
continue;
new_b.append(old_b);
new_s.append(old_s);
}
new_a = cell->connections.at("\\A");
if (new_a.is_fully_undef() && new_s.width > 0) {
new_a = new_b.extract((new_s.width-1)*width, width);
new_b = new_b.extract(0, (new_s.width-1)*width);
new_s = new_s.extract(0, new_s.width-1);
}
if (new_s.width == 0) {
replace_cell(module, cell, "mux undef", "\\Y", new_a);
goto next_cell;
}
if (new_a == RTLIL::SigSpec(RTLIL::State::S0) && new_b == RTLIL::SigSpec(RTLIL::State::S1)) {
replace_cell(module, cell, "mux undef", "\\Y", new_s);
goto next_cell;
}
if (cell->connections.at("\\S").width != new_s.width) {
cell->connections.at("\\A") = new_a;
cell->connections.at("\\B") = new_b;
cell->connections.at("\\S") = new_s;
if (new_s.width > 1) {
cell->type = "$pmux";
cell->parameters["\\S_WIDTH"] = new_s.width;
} else {
cell->type = "$mux";
cell->parameters.erase("\\S_WIDTH");
}
did_something = true;
}
}
#define FOLD_1ARG_CELL(_t) \
if (cell->type == "$" #_t) { \
RTLIL::SigSpec a = cell->connections["\\A"]; \
@ -312,25 +365,38 @@ struct OptConstPass : public Pass {
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" opt_const [selection]\n");
log(" opt_const [options] [selection]\n");
log("\n");
log("This pass performs const folding on internal cell types with constant inputs.\n");
log("\n");
log(" -mux_undef\n");
log(" remove 'undef' inputs from $mux, $pmux and $_MUX_ cells\n");
log("\n");
}
virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
{
bool mux_undef = false;
log_header("Executing OPT_CONST pass (perform const folding).\n");
log_push();
extra_args(args, 1, design);
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++) {
if (args[argidx] == "-mux_undef") {
mux_undef = true;
continue;
}
break;
}
extra_args(args, argidx, design);
for (auto &mod_it : design->modules)
do {
do {
did_something = false;
replace_const_cells(design, mod_it.second, false);
replace_const_cells(design, mod_it.second, false, mux_undef);
} while (did_something);
replace_const_cells(design, mod_it.second, true);
replace_const_cells(design, mod_it.second, true, mux_undef);
} while (did_something);
log_pop();