Enable Clock Invalidation (#2485) (#2487)

Loosen restrictions on clocks to enable them to be connected to
DontCare, i.e., be invalidated.

Co-authored-by: Jack Koenig <koenig@sifive.com>
Signed-off-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>

Co-authored-by: Jack Koenig <koenig@sifive.com>
(cherry picked from commit 5d8a0c8e406376f7ceda91273fb0fa7a646865aa)

Co-authored-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/core/src/main/scala/chisel3/Clock.scala b/core/src/main/scala/chisel3/Clock.scala
index 68174d7c..64e91c42 100644
--- a/core/src/main/scala/chisel3/Clock.scala
+++ b/core/src/main/scala/chisel3/Clock.scala
@@ -23,7 +23,7 @@ sealed class Clock(private[chisel3] val width: Width = Width(1)) extends Element
 
   override def connect(that: Data)(implicit sourceInfo: SourceInfo, connectCompileOptions: CompileOptions): Unit =
     that match {
-      case _: Clock => super.connect(that)(sourceInfo, connectCompileOptions)
+      case _: Clock | DontCare => super.connect(that)(sourceInfo, connectCompileOptions)
       case _ => super.badConnect(that)(sourceInfo)
     }