diff --git a/src/librustc_mir/interpret/step.rs b/src/librustc_mir/interpret/step.rs
index 55b9427a75ba3..33ed69af6ba02 100644
--- a/src/librustc_mir/interpret/step.rs
+++ b/src/librustc_mir/interpret/step.rs
@@ -304,7 +304,9 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         if !self.stack.is_empty() {
             // This should change *something*
             debug_assert!(self.cur_frame() != old_stack || self.frame().block != old_bb);
-            info!("// {:?}", self.frame().block);
+            if let Some(block) = self.frame().block {
+                info!("// executing {:?}", block);
+            }
         }
         Ok(())
     }