TEMP: try to reproduce earlier perf results

Author: RalfJung

compiler/rustc_const_eval/src/interpret/machine.rs

@@ -423,14 +423,14 @@ pub trait Machine<'mir, 'tcx: 'mir>: Sized {
     /// These places need to be protected to make sure the program cannot tell whether the
     /// argument/return value was actually copied or passed in-place.
     fn protect_in_place_function_argument(
-        ecx: &mut InterpCx<'mir, 'tcx, Self>,
-        place: &PlaceTy<'tcx, Self::Provenance>,
+        _ecx: &mut InterpCx<'mir, 'tcx, Self>,
+        _place: &PlaceTy<'tcx, Self::Provenance>,
     ) -> InterpResult<'tcx> {
         // Without an aliasing model, all we can do is put `Uninit` into the place.
         // This can only be violated with custom MIR though so we avoid the perf hit.
-        if ecx.tcx.sess.opts.unstable_opts.extra_const_ub_checks {
-            ecx.write_uninit(place)?;
-        }
+        //if ecx.tcx.sess.opts.unstable_opts.extra_const_ub_checks {
+        //    ecx.write_uninit(place)?;
+        //}
         Ok(())
     }