Index: llvm/lib/CodeGen/GlobalISel/Utils.cpp
===================================================================
--- llvm/lib/CodeGen/GlobalISel/Utils.cpp
+++ llvm/lib/CodeGen/GlobalISel/Utils.cpp
@@ -588,6 +588,17 @@
 
     break;
   }
+  case TargetOpcode::G_BUILD_VECTOR:
+  case TargetOpcode::G_BUILD_VECTOR_TRUNC: {
+    // TODO: Probably should have a recursion depth guard since you could have
+    // bitcasted vector elements.
+    for (unsigned I = 1, E = MI.getNumOperands(); I != E; ++I) {
+      if (!isKnownToBeAPowerOfTwo(MI.getOperand(I).getReg(), MRI, KB))
+        return false;
+    }
+
+    return true;
+  }
   default:
     break;
   }