diff --git a/src/librustc/mir/mod.rs b/src/librustc/mir/mod.rs
index a177b9055c5c..f18125692589 100644
--- a/src/librustc/mir/mod.rs
+++ b/src/librustc/mir/mod.rs
@@ -1150,7 +1150,7 @@ impl<'tcx> TerminatorKind<'tcx> {
             Goto { .. } => vec!["".into()],
             SwitchInt { ref values, switch_ty, .. } => {
                 let size = ty::tls::with(|tcx| switch_ty.scalar_size(tcx));
-                let size = size.map_or(0, |size| size.bytes()) as u8;
+                let size = size.map_or(0, |size| size.bits()) as u8;
                 values.iter()
                       .map(|&u| {
                           let mut s = String::new();