diff --git a/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp b/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
--- a/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
@@ -2868,9 +2868,11 @@
       case MVT::i8:
         ImmVal &= 0xFF;
         ImmVal |= (ImmVal << 8);
+        LLVM_FALLTHROUGH;
       case MVT::i16:
         ImmVal &= 0xFFFF;
         ImmVal |= (ImmVal << 16);
+        LLVM_FALLTHROUGH;
       case MVT::i32:
         ImmVal &= 0xFFFFFFFF;
         ImmVal |= (ImmVal << 32);