diff --git a/lib/Target/ARM/ARMFastISel.cpp b/lib/Target/ARM/ARMFastISel.cpp
index 16383bfeef1..62bc782c96a 100644
--- a/lib/Target/ARM/ARMFastISel.cpp
+++ b/lib/Target/ARM/ARMFastISel.cpp
@@ -2662,6 +2662,7 @@ unsigned ARMFastISel::ARMEmitIntExt(MVT SrcVT, unsigned SrcReg, MVT DestVT,
 
   unsigned SrcBits = SrcVT.getSizeInBits();
   unsigned DestBits = DestVT.getSizeInBits();
+  (void) DestBits;
   assert((SrcBits < DestBits) && "can only extend to larger types");
   assert((DestBits == 32 || DestBits == 16 || DestBits == 8) &&
          "other sizes unimplemented");