Add StringRef::contains()

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280113 91177308-0d34-0410-b5e6-96231b3b80d8

Author: Zachary Turner

include/llvm/ADT/StringRef.h

@@ -337,6 +337,11 @@ namespace llvm {
     /// Complexity: O(size() + Chars.size())
     size_t find_last_not_of(StringRef Chars, size_t From = npos) const;
 
+    /// Return true if the given string is a substring of *this, and false
+    /// otherwise.
+    LLVM_ATTRIBUTE_ALWAYS_INLINE
+    bool contains(StringRef Other) const { return find(Other) != npos; }
+
     /// @}
     /// @name Helpful Algorithms
     /// @{