add optional directionality assumption to BiConnect.elemConnect

1 files changed, 12 insertions, 2 deletions

diff --git a/chiselFrontend/src/main/scala/chisel3/core/BiConnect.scala b/chiselFrontend/src/main/scala/chisel3/core/BiConnect.scala
index b0be1c38..ce70a19a 100644
--- a/chiselFrontend/src/main/scala/chisel3/core/BiConnect.scala
+++ b/chiselFrontend/src/main/scala/chisel3/core/BiConnect.scala
@@ -217,8 +217,18 @@ object BiConnect {
 
         case (Some(Input),  Some(Input))  => throw NeitherDriverException
         case (Some(Output), Some(Output)) => throw BothDriversException
-        case (_, None)                    => throw UnknownRelationException
-        case (None, _)                    => throw UnknownRelationException
+        case (_, None)                    =>
+          if (connectCompileOptions.dontAssumeDirectionality) {
+            throw UnknownRelationException
+          } else {
+            issueConnectR2L(left, right)
+          }
+        case (None, _)                    =>
+          if (connectCompileOptions.dontAssumeDirectionality) {
+            throw UnknownRelationException
+          } else {
+            issueConnectR2L(left, right)
+          }
       }
     }