Address Richard's review comments on r147561 (Evaluate support for address-of-label differences).

llvm-svn: 147631
diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index 2c15132..826a950 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -1034,7 +1034,7 @@
       RHS = llvm::ConstantExpr::getPtrToInt(RHS, IntPtrTy);
       llvm::Constant *AddrLabelDiff = llvm::ConstantExpr::getSub(LHS, RHS);
 
-      // LLVM os a bit sensitive about the exact format of the
+      // LLVM is a bit sensitive about the exact format of the
       // address-of-label difference; make sure to truncate after
       // the subtraction.
       return llvm::ConstantExpr::getTruncOrBitCast(AddrLabelDiff, ResultType);