diff --git a/src/terminator/intrinsic.rs b/src/terminator/intrinsic.rs
index 9c7489d145c..56d097289bc 100644
--- a/src/terminator/intrinsic.rs
+++ b/src/terminator/intrinsic.rs
@@ -406,18 +406,11 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
                 let u8 = self.tcx.types.u8;
                 let ty = substs.type_at(0);
                 let size = self.type_size(ty)?.expect("write_bytes() type must be sized");
-                let val_byte = self.value_to_primval(arg_vals[1], u8)?.to_u128()?;
-                let mut pattern: u128 = 0;
-                for ii in 0..size {
-                    pattern |= val_byte << (8 * ii);
-                }
-                let val_full = Value::ByVal(PrimVal::from_u128(pattern));
                 let mut ptr = arg_vals[0].read_ptr(&self.memory)?;
-
                 let count = self.value_to_primval(arg_vals[2], usize)?.to_u64()?;
-                for _ in 0..count {
-                    self.write_value_to_ptr(val_full, ptr, ty)?;
-                    ptr = ptr.offset(size);
+                for _ in 0..(count * size) {
+                    self.write_value_to_ptr(arg_vals[1], ptr, u8)?;
+                    ptr = ptr.offset(1);
                 }
             }