diff --git a/compiler/utils/arm/assembler_thumb2.cc b/compiler/utils/arm/assembler_thumb2.cc
index e95db0d..a894319 100644
--- a/compiler/utils/arm/assembler_thumb2.cc
+++ b/compiler/utils/arm/assembler_thumb2.cc
@@ -924,6 +924,8 @@
       use_immediate = true;
       immediate = so.GetImmediate();
     } else {
+      CHECK(!(so.IsRegister() && so.IsShift() && so.GetSecondRegister() != kNoRegister))
+          << "No register-shifted register instruction available in thumb";
       // Adjust rn and rd: only two registers will be emitted.
       switch (opcode) {
         case AND: