diff --git a/llvm/lib/IR/AttributeImpl.h b/llvm/lib/IR/AttributeImpl.h
--- a/llvm/lib/IR/AttributeImpl.h
+++ b/llvm/lib/IR/AttributeImpl.h
@@ -16,6 +16,7 @@
 #define LLVM_LIB_IR_ATTRIBUTEIMPL_H
 
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/FoldingSet.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/IR/Attributes.h"
@@ -181,6 +182,8 @@
   /// Bitset with a bit for each available attribute Attribute::AttrKind.
   uint8_t AvailableAttrs[12] = {};
 
+  DenseMap<StringRef, Attribute> StringAttrs;
+
   AttributeSetNode(ArrayRef<Attribute> Attrs);
 
 public:
diff --git a/llvm/lib/IR/Attributes.cpp b/llvm/lib/IR/Attributes.cpp
--- a/llvm/lib/IR/Attributes.cpp
+++ b/llvm/lib/IR/Attributes.cpp
@@ -770,7 +770,9 @@
                 "Too many attributes");
 
   for (const auto &I : *this) {
-    if (!I.isStringAttribute()) {
+    if (I.isStringAttribute()) {
+      StringAttrs.insert({ I.getKindAsString(), I });
+    } else {
       Attribute::AttrKind Kind = I.getKindAsEnum();
       AvailableAttrs[Kind / 8] |= 1ULL << (Kind % 8);
     }
@@ -857,10 +859,7 @@
 }
 
 bool AttributeSetNode::hasAttribute(StringRef Kind) const {
-  for (const auto &I : *this)
-    if (I.hasAttribute(Kind))
-      return true;
-  return false;
+  return StringAttrs.count(Kind);
 }
 
 Attribute AttributeSetNode::getAttribute(Attribute::AttrKind Kind) const {
@@ -873,10 +872,7 @@
 }
 
 Attribute AttributeSetNode::getAttribute(StringRef Kind) const {
-  for (const auto &I : *this)
-    if (I.hasAttribute(Kind))
-      return I;
-  return {};
+  return StringAttrs.lookup(Kind);
 }
 
 MaybeAlign AttributeSetNode::getAlignment() const {