Index: llvm/trunk/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
===================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
+++ llvm/trunk/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
@@ -1512,7 +1512,7 @@
 
   // Because of simplify-demanded-bits in DAGCombine, the mask may have been
   // simplified. Try to undo that
-  AndImm |= (1 << NumberOfIgnoredLowBits) - 1;
+  AndImm |= maskTrailingOnes<uint64_t>(NumberOfIgnoredLowBits);
 
   // The immediate is a mask of the low bits iff imm & (imm+1) == 0
   if (AndImm & (AndImm + 1))