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wreduce: Adjust naming and comments

This commit is contained in:
Martin Povišer 2025-01-03 12:54:34 +01:00
parent 08778917db
commit be351886a5
1 changed files with 9 additions and 8 deletions
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17
passes/opt/wreduce.cc
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@ -308,7 +308,8 @@ struct WreduceWorker
bool port_a_signed = false; bool port_a_signed = false;
bool port_b_signed = false; bool port_b_signed = false;
// Under certain conditions we are free to choose the signedness of the operands // For some operations if the output is no wider than either of the inputs
// we are free to choose the signedness of the operands
if (cell->type.in(ID($mul), ID($add), ID($sub)) && if (cell->type.in(ID($mul), ID($add), ID($sub)) &&
max_port_a_size == GetSize(sig) && max_port_a_size == GetSize(sig) &&
max_port_b_size == GetSize(sig)) { max_port_b_size == GetSize(sig)) {
@ -318,16 +319,16 @@ struct WreduceWorker
sig_a.extend_u0(max_port_a_size); sig_a.extend_u0(max_port_a_size);
sig_b.extend_u0(max_port_b_size); sig_b.extend_u0(max_port_b_size);
int signed_size, unsigned_size; int signed_cost, unsigned_cost;
if (cell->type == ID($mul)) { if (cell->type == ID($mul)) {
signed_size = reduced_opsize(sig_a, true) * reduced_opsize(sig_b, true); signed_cost = reduced_opsize(sig_a, true) * reduced_opsize(sig_b, true);
unsigned_size = reduced_opsize(sig_a, false) * reduced_opsize(sig_b, false); unsigned_cost = reduced_opsize(sig_a, false) * reduced_opsize(sig_b, false);
} else { } else {
signed_size = max(reduced_opsize(sig_a, true), reduced_opsize(sig_b, true)); signed_cost = max(reduced_opsize(sig_a, true), reduced_opsize(sig_b, true));
unsigned_size = max(reduced_opsize(sig_a, false), reduced_opsize(sig_b, false)); unsigned_cost = max(reduced_opsize(sig_a, false), reduced_opsize(sig_b, false));
} }
if (!port_a_signed && !port_b_signed && signed_size < unsigned_size) { if (!port_a_signed && !port_b_signed && signed_cost < unsigned_cost) {
log("Converting cell %s.%s (%s) from unsigned to signed.\n", log("Converting cell %s.%s (%s) from unsigned to signed.\n",
log_id(module), log_id(cell), log_id(cell->type)); log_id(module), log_id(cell), log_id(cell->type));
cell->setParam(ID::A_SIGNED, 1); cell->setParam(ID::A_SIGNED, 1);
@ -335,7 +336,7 @@ struct WreduceWorker
port_a_signed = true; port_a_signed = true;
port_b_signed = true; port_b_signed = true;
did_something = true; did_something = true;
} else if (port_a_signed && port_b_signed && unsigned_size < signed_size) { } else if (port_a_signed && port_b_signed && unsigned_cost < signed_cost) {
log("Converting cell %s.%s (%s) from signed to unsigned.\n", log("Converting cell %s.%s (%s) from signed to unsigned.\n",
log_id(module), log_id(cell), log_id(cell->type)); log_id(module), log_id(cell), log_id(cell->type));
cell->setParam(ID::A_SIGNED, 0); cell->setParam(ID::A_SIGNED, 0);