Add a way to add a kind-value string pair to an attribute.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187138 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/IR/Attributes.cpp b/lib/IR/Attributes.cpp
index 48743fa..894ff7d 100644
--- a/lib/IR/Attributes.cpp
+++ b/lib/IR/Attributes.cpp
@@ -645,6 +645,13 @@
   return addAttributes(C, Index, AttributeSet::get(C, Index, B));
 }
 
+AttributeSet AttributeSet::addAttribute(LLVMContext &C, unsigned Index,
+                                        StringRef Kind, StringRef Value) const {
+  llvm::AttrBuilder B;
+  B.addAttribute(Kind, Value);
+  return addAttributes(C, Index, AttributeSet::get(C, Index, B));
+}
+
 AttributeSet AttributeSet::addAttributes(LLVMContext &C, unsigned Index,
                                          AttributeSet Attrs) const {
   if (!pImpl) return Attrs;