fix typos in comments and error messages; NFC

llvm-svn: 307533
diff --git a/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp b/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
index b235e19..b96c96f 100644
--- a/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
@@ -589,7 +589,7 @@
     } else
       AddOperand(MIB, N0, 0, nullptr, VRBaseMap, /*IsDebug=*/false,
                  IsClone, IsCloned);
-    // Add the subregster being inserted
+    // Add the subregister being inserted
     AddOperand(MIB, N1, 0, nullptr, VRBaseMap, /*IsDebug=*/false,
                IsClone, IsCloned);
     MIB.addImm(SubIdx);