diff --git a/artiq/devices/runtime.py b/artiq/devices/runtime.py
index 1c8d88275..a4a55f77f 100644
--- a/artiq/devices/runtime.py
+++ b/artiq/devices/runtime.py
@@ -57,7 +57,7 @@ class LinkInterface:
     def syscall(self, syscall_name, args, builder):
         r = _chr_to_value[_syscalls[syscall_name][-1]]()
         if builder is not None:
-            args = [arg.get_ssa_value(builder) for arg in args]
+            args = [arg.auto_load(builder) for arg in args]
             if syscall_name in self.var_arg_fixcount:
                 fixcount = self.var_arg_fixcount[syscall_name]
                 args = args[:fixcount] \
@@ -65,7 +65,7 @@ class LinkInterface:
                     + args[fixcount:]
             llvm_function = self.llvm_module.get_function_named(
                 "__syscall_" + syscall_name)
-            r.set_ssa_value(builder, builder.call(llvm_function, args))
+            r.auto_store(builder, builder.call(llvm_function, args))
         return r