diff --git a/pcbnew/board.cpp b/pcbnew/board.cpp
index b2f505bb82..783c8384f7 100644
--- a/pcbnew/board.cpp
+++ b/pcbnew/board.cpp
@@ -198,6 +198,7 @@ void BOARD::IncrementTimeStamp()
         m_InsideCourtyardCache.clear();
         m_InsideFCourtyardCache.clear();
         m_InsideBCourtyardCache.clear();
+        m_LayerExpressionCache.clear();
     }
 
     m_CopperZoneRTrees.clear();
diff --git a/pcbnew/board.h b/pcbnew/board.h
index 6eb1aac897..87520c4473 100644
--- a/pcbnew/board.h
+++ b/pcbnew/board.h
@@ -1084,6 +1084,7 @@ public:
     std::map< std::pair<BOARD_ITEM*, BOARD_ITEM*>, bool > m_InsideFCourtyardCache;
     std::map< std::pair<BOARD_ITEM*, BOARD_ITEM*>, bool > m_InsideBCourtyardCache;
     std::map< std::pair<BOARD_ITEM*, BOARD_ITEM*>, bool > m_InsideAreaCache;
+    std::map< wxString, LSET >                            m_LayerExpressionCache;
 
     std::map< ZONE*, std::unique_ptr<DRC_RTREE> >         m_CopperZoneRTrees;
 
diff --git a/pcbnew/pcb_expr_evaluator.cpp b/pcbnew/pcb_expr_evaluator.cpp
index b29778181f..2189f9e9ff 100644
--- a/pcbnew/pcb_expr_evaluator.cpp
+++ b/pcbnew/pcb_expr_evaluator.cpp
@@ -100,26 +100,65 @@ static void existsOnLayer( LIBEVAL::CONTEXT* aCtx, void *self )
 
     wxString     layerName = arg->AsString();
     wxPGChoices& layerMap = ENUM_MAP<PCB_LAYER_ID>::Instance().Choices();
-    bool         anyMatch = false;
 
-    for( unsigned ii = 0; ii < layerMap.GetCount(); ++ii )
+    if( aCtx->HasErrorCallback() )
     {
-        wxPGChoiceEntry& entry = layerMap[ii];
+        /*
+         * Interpreted version
+         */
 
-        if( entry.GetText().Matches( layerName ) )
+        bool anyMatch = false;
+
+        for( unsigned ii = 0; ii < layerMap.GetCount(); ++ii )
         {
-            anyMatch = true;
+            wxPGChoiceEntry& entry = layerMap[ii];
 
-            if( item->IsOnLayer( ToLAYER_ID( entry.GetValue() ) ) )
+            if( entry.GetText().Matches( layerName ) )
             {
-                result->Set( 1.0 );
-                return;
+                anyMatch = true;
+
+                if( item->IsOnLayer( ToLAYER_ID( entry.GetValue() ) ) )
+                {
+                    result->Set( 1.0 );
+                    return;
+                }
             }
         }
-    }
 
-    if( !anyMatch && aCtx->HasErrorCallback() )
-        aCtx->ReportError( wxString::Format( _( "Unrecognized layer '%s'" ), layerName ) );
+        if( !anyMatch )
+            aCtx->ReportError( wxString::Format( _( "Unrecognized layer '%s'" ), layerName ) );
+    }
+    else
+    {
+        /*
+         * Compiled version
+         */
+
+        BOARD*                       board = item->GetBoard();
+        std::unique_lock<std::mutex> cacheLock( board->m_CachesMutex );
+        auto                         i = board->m_LayerExpressionCache.find( layerName );
+        LSET                         mask;
+
+        if( i == board->m_LayerExpressionCache.end() )
+        {
+            for( unsigned ii = 0; ii < layerMap.GetCount(); ++ii )
+            {
+                wxPGChoiceEntry& entry = layerMap[ii];
+
+                if( entry.GetText().Matches( layerName ) )
+                    mask.set( ToLAYER_ID( entry.GetValue() ) );
+            }
+
+            board->m_LayerExpressionCache[ layerName ] = mask;
+        }
+        else
+        {
+            mask = i->second;
+        }
+
+        if( ( item->GetLayerSet() & mask ).any() )
+            result->Set( 1.0 );
+    }
 }