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-rw-r--r--passes/opt/wreduce.cc29
1 files changed, 26 insertions, 3 deletions
diff --git a/passes/opt/wreduce.cc b/passes/opt/wreduce.cc
index 1fbc41082..dff1c5370 100644
--- a/passes/opt/wreduce.cc
+++ b/passes/opt/wreduce.cc
@@ -342,9 +342,9 @@ struct WreduceWorker
}
}
- if (cell->type.in("$pos", "$add", "$mul", "$and", "$or", "$xor"))
+ if (cell->type.in("$pos", "$add", "$mul", "$and", "$or", "$xor", "$sub"))
{
- bool is_signed = cell->getParam("\\A_SIGNED").as_bool();
+ bool is_signed = cell->getParam("\\A_SIGNED").as_bool() || cell->type == "$sub";
int a_size = 0, b_size = 0;
if (cell->hasPort("\\A")) a_size = GetSize(cell->getPort("\\A"));
@@ -352,7 +352,7 @@ struct WreduceWorker
int max_y_size = max(a_size, b_size);
- if (cell->type == "$add")
+ if (cell->type.in("$add", "$sub"))
max_y_size++;
if (cell->type == "$mul")
@@ -365,6 +365,29 @@ struct WreduceWorker
}
}
+ if (cell->type.in("$add", "$sub")) {
+ SigSpec A = cell->getPort("\\A");
+ SigSpec B = cell->getPort("\\B");
+ bool sub = cell->type == "$sub";
+
+ int i;
+ for (i = 0; i < GetSize(sig); i++) {
+ if (B[i] != S0 && (sub || A[i] != S0))
+ break;
+ if (B[i] == S0)
+ module->connect(sig[i], A[i]);
+ else if (A[i] == S0)
+ module->connect(sig[i], B[i]);
+ else log_abort();
+ }
+ if (i > 0) {
+ cell->setPort("\\A", A.extract(i, -1));
+ cell->setPort("\\B", B.extract(i, -1));
+ sig.remove(0, i);
+ bits_removed += i;
+ }
+ }
+
if (GetSize(sig) == 0) {
log("Removed cell %s.%s (%s).\n", log_id(module), log_id(cell), log_id(cell->type));
module->remove(cell);