Fix #1220: Allow uwire arrays as input ports

Uwire arrays were triggering assertion failures because they were
kept virtualized (pins array NULL) like reg arrays. However, unlike
reg arrays, uwire arrays used as input ports need their nexuses
initialized for the target code generation to work properly.

Two changes:
1. elab_sig.cc: Devirtualize pins for UNRESOLVED_WIRE (uwire) type,
   same as regular WIRE type.
2. t-dll-api.cc: Update assertion in ivl_signal_nex to also accept
   IVL_SIT_UWIRE when pins array is NULL.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

elab_sig.cc

@@ -1210,7 +1210,8 @@ NetNet* PWire::elaborate_sig(Design*des, NetScope*scope)
 
       NetNet*sig = new NetNet(scope, name_, wtype, unpacked_dimensions, type);
 
-      if (wtype == NetNet::WIRE) sig->devirtualize_pins();
+      if (wtype == NetNet::WIRE || wtype == NetNet::UNRESOLVED_WIRE)
+	    sig->devirtualize_pins();
       sig->set_line(*this);
       sig->port_type(port_type_);
       sig->lexical_pos(lexical_pos_);

ivtest/ivltests/br_gh1220.v

@@ -0,0 +1,19 @@
+// Test for GitHub issue #1220
+// Assertion failed with uwire multi-dimensional input port
+module sub(input uwire data [1:0]);
+  initial begin
+    #1;
+    if (data[0] === 1'b0 && data[1] === 1'b1)
+      $display("PASSED");
+    else
+      $display("FAILED: data[0]=%0b data[1]=%0b", data[0], data[1]);
+  end
+endmodule
+
+module test;
+  wire w [1:0];
+  assign w[0] = 1'b0;
+  assign w[1] = 1'b1;
+
+  sub dut(.data(w));
+endmodule

ivtest/regress-sv.list

@@ -229,6 +229,7 @@ br_gh782b		normal,-g2009		ivltests gold=br_gh782b.gold
 br_gh800		normal,-g2009		ivltests
 br_gh801		normal,-g2012		ivltests
 br_gh801b		normal,-g2012		ivltests
+br_gh1220		normal,-g2012		ivltests
 br_gh1222		CE,-g2009		ivltests gold=br_gh1222.gold
 br_gh1223a		normal,-g2009		ivltests
 br_gh1223b		normal,-g2009		ivltests

t-dll-api.cc

@@ -2496,8 +2496,8 @@ extern "C" ivl_nexus_t ivl_signal_nex(ivl_signal_t net, unsigned word)
 	    if (net->pins) {
 		return net->pins[word];
 	    } else {
-		// net->pins can be NULL for a virtualized reg array.
-		assert(net->type_ == IVL_SIT_REG);
+		// net->pins can be NULL for a virtualized reg or uwire array.
+		assert(net->type_ == IVL_SIT_REG || net->type_ == IVL_SIT_UWIRE);
 		return NULL;
 	    }
       } else {