diff --git a/gdb/nacl-tdep.c b/gdb/nacl-tdep.c
index 0032c20..7039b2c 100644
--- a/gdb/nacl-tdep.c
+++ b/gdb/nacl-tdep.c
@@ -184,6 +184,12 @@
   return frame_id_build (fp, get_frame_pc (this_frame));
 }
 
+static int
+amd64_nacl_inner_than (CORE_ADDR lhs, CORE_ADDR rhs)
+{
+  return (uint32_t)lhs < (uint32_t)rhs;
+}
+
 static void
 amd64_nacl_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
@@ -217,6 +223,7 @@
   set_gdbarch_addr_bits_remove (gdbarch, amd64_nacl_addr_bits_remove);
   set_gdbarch_unwind_pc (gdbarch, amd64_nacl_unwind_pc);
   set_gdbarch_unwind_sp (gdbarch, amd64_nacl_unwind_sp);
+  set_gdbarch_inner_than (gdbarch, amd64_nacl_inner_than);
 
   /* Where to set breakpoints.  */
   set_gdbarch_adjust_breakpoint_address (gdbarch,