Index: llvm/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
===================================================================
--- llvm/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
+++ llvm/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
@@ -1138,6 +1138,7 @@
   // representation for the complex operand in the .td file. This isn't just
   // style, unfortunately. As-is, we can't represent the distinct encoding
   // for #-0.
+  assert(((Imm8 & 0x3) == 0) && "Not a valid immediate!");
   uint32_t Binary = (Imm8 >> 2) & 0xff;
   // Immediate is always encoded as positive. The 'U' bit controls add vs sub.
   if (isAdd)