Return the original signal when replicating by 1

lib/src/signals/logic.dart

@@ -962,8 +962,16 @@ class Logic {
   /// The input [multiplier] cannot be negative or 0; an exception will be
   /// thrown, otherwise.
   ///
+  /// If [multiplier] is 1, then this signal is returned directly, since
+  /// replicating once is a no-op and would otherwise generate a redundant
+  /// `1{...}` in the output SystemVerilog.
+  ///
   /// If [isNet], then the result will also be a net.
   Logic replicate(int multiplier) {
+    if (multiplier == 1) {
+      return this;
+    }
+
     if (isNet) {
       // many SV simulators don't support replication of nets
       return List.generate(multiplier, (i) => this).swizzle();

test/replication_test.dart

@@ -1,4 +1,4 @@
-// Copyright (C) 2023 Intel Corporation
+// Copyright (C) 2023-2026 Intel Corporation
 // SPDX-License-Identifier: BSD-3-Clause
 //
 // replication_test.dart
@@ -21,6 +21,13 @@ class ReplicationOpModule extends Module {
   }
 }
 
+class SignExtendModule extends Module {
+  SignExtendModule(Logic a, int newWidth) {
+    a = addInput('a', a, width: a.width);
+    addOutput('b', width: newWidth) <= a.signExtend(newWidth);
+  }
+}
+
 void main() {
   group('Logic', () {
     tearDown(Simulator.reset);
@@ -52,6 +59,27 @@ void main() {
         ], 1, originalWidth: 4);
       });
 
+      test('multiply by 1 returns the original signal', () {
+        final a = Logic(width: 4);
+        expect(identical(a.replicate(1), a), isTrue);
+      });
+
+      test('multiply by 1 generates no replication in SystemVerilog', () async {
+        final mod = ReplicationOpModule(Logic(width: 4), 1);
+        await mod.build();
+        final sv = mod.generateSynth();
+        expect(sv, contains('assign b = a;'));
+        expect(sv, isNot(contains('{1{')));
+      });
+
+      test('signExtend of a 1-bit signal by 1 generates no replication',
+          () async {
+        final mod = SignExtendModule(Logic(), 1);
+        await mod.build();
+        final sv = mod.generateSynth();
+        expect(sv, isNot(contains('{1{')));
+      });
+
       test('multiply by 2 replicates the input signal twice', () async {
         await replicateVectors([
           Vector({'a': 0}, {'b': 0}),