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-rw-r--r--passes/opt/opt_expr.cc110
1 files changed, 88 insertions, 22 deletions
diff --git a/passes/opt/opt_expr.cc b/passes/opt/opt_expr.cc
index 68d6ea82b..a92643134 100644
--- a/passes/opt/opt_expr.cc
+++ b/passes/opt/opt_expr.cc
@@ -495,6 +495,42 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool cons
}
}
+ if (cell->type.in(ID($_XOR_), ID($_XNOR_)) || (cell->type.in(ID($xor), ID($xnor)) && GetSize(cell->getPort(ID::A)) == 1 && GetSize(cell->getPort(ID::B)) == 1 && !cell->getParam(ID(A_SIGNED)).as_bool()))
+ {
+ SigBit sig_a = assign_map(cell->getPort(ID::A));
+ SigBit sig_b = assign_map(cell->getPort(ID::B));
+ if (!sig_a.wire)
+ std::swap(sig_a, sig_b);
+ if (sig_b == State::S0 || sig_b == State::S1) {
+ if (cell->type.in(ID($xor), ID($_XOR_))) {
+ cover("opt.opt_expr.xor_buffer");
+ SigSpec sig_y;
+ if (cell->type == ID($xor))
+ sig_y = (sig_b == State::S1 ? module->Not(NEW_ID, sig_a).as_bit() : sig_a);
+ else if (cell->type == ID($_XOR_))
+ sig_y = (sig_b == State::S1 ? module->NotGate(NEW_ID, sig_a) : sig_a);
+ else log_abort();
+ replace_cell(assign_map, module, cell, "xor_buffer", ID::Y, sig_y);
+ goto next_cell;
+ }
+ if (cell->type.in(ID($xnor), ID($_XNOR_))) {
+ cover("opt.opt_expr.xnor_buffer");
+ SigSpec sig_y;
+ if (cell->type == ID($xnor)) {
+ sig_y = (sig_b == State::S1 ? sig_a : module->Not(NEW_ID, sig_a).as_bit());
+ int width = cell->getParam(ID(Y_WIDTH)).as_int();
+ sig_y.append(RTLIL::Const(State::S1, width-1));
+ }
+ else if (cell->type == ID($_XNOR_))
+ sig_y = (sig_b == State::S1 ? sig_a : module->NotGate(NEW_ID, sig_a));
+ else log_abort();
+ replace_cell(assign_map, module, cell, "xnor_buffer", ID::Y, sig_y);
+ goto next_cell;
+ }
+ log_abort();
+ }
+ }
+
if (cell->type.in(ID($reduce_and), ID($reduce_or), ID($reduce_bool), ID($reduce_xor), ID($reduce_xnor), ID($neg)) &&
GetSize(cell->getPort(ID::A)) == 1 && GetSize(cell->getPort(ID::Y)) == 1)
{
@@ -650,10 +686,14 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool cons
int i;
for (i = 0; i < GetSize(sig_y); i++) {
- if (sig_b.at(i, State::Sx) == State::S0 && sig_a.at(i, State::Sx) != State::Sx)
- module->connect(sig_y[i], sig_a[i]);
- else if (!sub && sig_a.at(i, State::Sx) == State::S0 && sig_b.at(i, State::Sx) != State::Sx)
- module->connect(sig_y[i], sig_b[i]);
+ RTLIL::SigBit b = sig_b.at(i, State::Sx);
+ RTLIL::SigBit a = sig_a.at(i, State::Sx);
+ if (b == State::S0 && a != State::Sx)
+ module->connect(sig_y[i], a);
+ else if (sub && b == State::S1 && a == State::S1)
+ module->connect(sig_y[i], State::S0);
+ else if (!sub && a == State::S0 && b != State::Sx)
+ module->connect(sig_y[i], b);
else
break;
}
@@ -667,7 +707,7 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool cons
}
}
- if (cell->type == "$alu")
+ if (cell->type == ID($alu))
{
RTLIL::SigSpec sig_a = assign_map(cell->getPort(ID::A));
RTLIL::SigSpec sig_b = assign_map(cell->getPort(ID::B));
@@ -677,9 +717,6 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool cons
RTLIL::SigSpec sig_y = cell->getPort(ID::Y);
RTLIL::SigSpec sig_co = cell->getPort(ID(CO));
- if (sig_ci.wire || sig_bi.wire)
- goto next_cell;
-
bool sub = (sig_ci == State::S1 && sig_bi == State::S1);
// If not a subtraction, yet there is a carry or B is inverted
@@ -689,14 +726,21 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool cons
int i;
for (i = 0; i < GetSize(sig_y); i++) {
- if (sig_b.at(i, State::Sx) == State::S0 && sig_a.at(i, State::Sx) != State::Sx) {
- module->connect(sig_x[i], sub ? module->Not(NEW_ID, sig_a[i]).as_bit() : sig_a[i]);
+ RTLIL::SigBit b = sig_b.at(i, State::Sx);
+ RTLIL::SigBit a = sig_a.at(i, State::Sx);
+ if (b == State::S0 && a != State::Sx) {
module->connect(sig_y[i], sig_a[i]);
+ module->connect(sig_x[i], sub ? module->Not(NEW_ID, a).as_bit() : a);
module->connect(sig_co[i], sub ? State::S1 : State::S0);
}
- else if (!sub && sig_a.at(i, State::Sx) == State::S0 && sig_b.at(i, State::Sx) != State::Sx) {
- module->connect(sig_x[i], sig_b[i]);
- module->connect(sig_y[i], sig_b[i]);
+ else if (sub && b == State::S1 && a == State::S1) {
+ module->connect(sig_y[i], State::S0);
+ module->connect(sig_x[i], module->Not(NEW_ID, a));
+ module->connect(sig_co[i], State::S0);
+ }
+ else if (!sub && a == State::S0 && b != State::Sx) {
+ module->connect(sig_y[i], b);
+ module->connect(sig_x[i], b);
module->connect(sig_co[i], State::S0);
}
else
@@ -841,8 +885,6 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool cons
if (input.match("11")) ACTION_DO_Y(0);
if (input.match(" *")) ACTION_DO_Y(x);
if (input.match("* ")) ACTION_DO_Y(x);
- if (input.match(" 0")) ACTION_DO(ID::Y, input.extract(1, 1));
- if (input.match("0 ")) ACTION_DO(ID::Y, input.extract(0, 1));
}
if (cell->type == ID($_MUX_)) {
@@ -1031,12 +1073,26 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool cons
bool identity_wrt_b = false;
bool arith_inverse = false;
- if (cell->type.in(ID($add), ID($sub), ID($or), ID($xor)))
+ if (cell->type.in(ID($add), ID($sub), ID($alu), ID($or), ID($xor)))
{
RTLIL::SigSpec a = assign_map(cell->getPort(ID::A));
RTLIL::SigSpec b = assign_map(cell->getPort(ID::B));
- if (cell->type != ID($sub) && a.is_fully_const() && a.as_bool() == false)
+ bool sub = cell->type == ID($sub);
+
+ if (cell->type == ID($alu)) {
+ RTLIL::SigBit sig_ci = assign_map(cell->getPort(ID(CI)));
+ RTLIL::SigBit sig_bi = assign_map(cell->getPort(ID(BI)));
+
+ sub = (sig_ci == State::S1 && sig_bi == State::S1);
+
+ // If not a subtraction, yet there is a carry or B is inverted
+ // then no optimisation is possible as carry will not be constant
+ if (!sub && (sig_ci != State::S0 || sig_bi != State::S0))
+ goto next_cell;
+ }
+
+ if (!sub && a.is_fully_const() && a.as_bool() == false)
identity_wrt_b = true;
if (b.is_fully_const() && b.as_bool() == false)
@@ -1074,17 +1130,27 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool cons
if (identity_wrt_a || identity_wrt_b)
{
if (identity_wrt_a)
- cover_list("opt.opt_expr.identwrt.a", "$add", "$sub", "$or", "$xor", "$shl", "$shr", "$sshl", "$sshr", "$shift", "$shiftx", "$mul", "$div", cell->type.str());
+ cover_list("opt.opt_expr.identwrt.a", "$add", "$sub", "$alu", "$or", "$xor", "$shl", "$shr", "$sshl", "$sshr", "$shift", "$shiftx", "$mul", "$div", cell->type.str());
if (identity_wrt_b)
- cover_list("opt.opt_expr.identwrt.b", "$add", "$sub", "$or", "$xor", "$shl", "$shr", "$sshl", "$sshr", "$shift", "$shiftx", "$mul", "$div", cell->type.str());
+ cover_list("opt.opt_expr.identwrt.b", "$add", "$sub", "$alu", "$or", "$xor", "$shl", "$shr", "$sshl", "$sshr", "$shift", "$shiftx", "$mul", "$div", cell->type.str());
log_debug("Replacing %s cell `%s' in module `%s' with identity for port %c.\n",
cell->type.c_str(), cell->name.c_str(), module->name.c_str(), identity_wrt_a ? 'A' : 'B');
+ if (cell->type == ID($alu)) {
+ int y_width = GetSize(cell->getPort(ID(Y)));
+ module->connect(cell->getPort(ID(X)), RTLIL::Const(State::S0, y_width));
+ module->connect(cell->getPort(ID(CO)), RTLIL::Const(State::S0, y_width));
+ cell->unsetPort(ID(BI));
+ cell->unsetPort(ID(CI));
+ cell->unsetPort(ID(X));
+ cell->unsetPort(ID(CO));
+ }
+
if (!identity_wrt_a) {
cell->setPort(ID::A, cell->getPort(ID::B));
- cell->parameters.at(ID(A_WIDTH)) = cell->parameters.at(ID(B_WIDTH));
- cell->parameters.at(ID(A_SIGNED)) = cell->parameters.at(ID(B_SIGNED));
+ cell->setParam(ID(A_WIDTH), cell->getParam(ID(B_WIDTH)));
+ cell->setParam(ID(A_SIGNED), cell->getParam(ID(B_SIGNED)));
}
cell->type = arith_inverse ? ID($neg) : ID($pos);
@@ -1589,7 +1655,7 @@ void replace_const_cells(RTLIL::Design *design, RTLIL::Module *module, bool cons
}
int const_bit_set = get_highest_hot_index(const_sig);
- if(const_bit_set >= var_width)
+ if (const_bit_set >= var_width)
{
string cmp_name;
if (cmp_type == ID($lt) || cmp_type == ID($le))
generated by cgit v1.2.3 (git 2.25.1) at 2025-04-04 22:09:36 +0000