Fix a tranche of comment, test and doc typos

llvm-svn: 196510
diff --git a/clang/lib/CodeGen/TargetInfo.h b/clang/lib/CodeGen/TargetInfo.h
index f631f31..b67b685 100644
--- a/clang/lib/CodeGen/TargetInfo.h
+++ b/clang/lib/CodeGen/TargetInfo.h
@@ -176,7 +176,7 @@
     /// However, some platforms make the conventions identical except
     /// for passing additional out-of-band information to a variadic
     /// function: for example, x86-64 passes the number of SSE
-    /// arguments in %al.  On these platforms, it is desireable to
+    /// arguments in %al.  On these platforms, it is desirable to
     /// call unprototyped functions using the variadic convention so
     /// that unprototyped calls to varargs functions still succeed.
     ///