diff --git a/compiler/utils/mips64/assembler_mips64.cc b/compiler/utils/mips64/assembler_mips64.cc
index 0cff44d..57223b5 100644
--- a/compiler/utils/mips64/assembler_mips64.cc
+++ b/compiler/utils/mips64/assembler_mips64.cc
@@ -1703,6 +1703,7 @@
 
 // TODO: don't use rtmp, use daui, dahi, dati.
 void Mips64Assembler::Daddiu64(GpuRegister rt, GpuRegister rs, int64_t value, GpuRegister rtmp) {
+  CHECK_NE(rs, rtmp);
   if (IsInt<16>(value)) {
     Daddiu(rt, rs, value);
   } else {