diff --git a/llvm/tools/llvm-reduce/deltas/Delta.cpp b/llvm/tools/llvm-reduce/deltas/Delta.cpp
index 0071cd0402dbd..932d7198e9791 100644
--- a/llvm/tools/llvm-reduce/deltas/Delta.cpp
+++ b/llvm/tools/llvm-reduce/deltas/Delta.cpp
@@ -136,7 +136,7 @@ static std::unique_ptr<ReducerWorkItem>
 CheckChunk(Chunk &ChunkToCheckForUninterestingness,
            std::unique_ptr<ReducerWorkItem> Clone, TestRunner &Test,
            ReductionFunc ExtractChunksFromModule,
-           std::set<Chunk> &UninterestingChunks,
+           DenseSet<Chunk> &UninterestingChunks,
            std::vector<Chunk> &ChunksStillConsideredInteresting) {
   // Take all of ChunksStillConsideredInteresting chunks, except those we've
   // already deemed uninteresting (UninterestingChunks) but didn't remove
@@ -188,7 +188,7 @@ CheckChunk(Chunk &ChunkToCheckForUninterestingness,
 
 static SmallString<0> ProcessChunkFromSerializedBitcode(
     Chunk &ChunkToCheckForUninterestingness, TestRunner &Test,
-    ReductionFunc ExtractChunksFromModule, std::set<Chunk> &UninterestingChunks,
+    ReductionFunc ExtractChunksFromModule, DenseSet<Chunk> &UninterestingChunks,
     std::vector<Chunk> &ChunksStillConsideredInteresting,
     SmallString<0> &OriginalBC, std::atomic<bool> &AnyReduced) {
   LLVMContext Ctx;
@@ -270,7 +270,7 @@ void llvm::runDeltaPass(TestRunner &Test, ReductionFunc ExtractChunksFromModule,
   do {
     FoundAtLeastOneNewUninterestingChunkWithCurrentGranularity = false;
 
-    std::set<Chunk> UninterestingChunks;
+    DenseSet<Chunk> UninterestingChunks;
 
     // When running with more than one thread, serialize the original bitcode
     // to OriginalBC.
diff --git a/llvm/tools/llvm-reduce/deltas/Delta.h b/llvm/tools/llvm-reduce/deltas/Delta.h
index e89cb72f10db9..6b595e796ef13 100644
--- a/llvm/tools/llvm-reduce/deltas/Delta.h
+++ b/llvm/tools/llvm-reduce/deltas/Delta.h
@@ -42,12 +42,39 @@ struct Chunk {
     return C1.Begin != C2.Begin || C1.End != C2.End;
   }
 
+  friend bool operator==(const Chunk &C1, const Chunk &C2) {
+    return C1.Begin == C2.Begin && C1.End == C2.End;
+  }
+
   /// Operator used for sets
   friend bool operator<(const Chunk &C1, const Chunk &C2) {
     return std::tie(C1.Begin, C1.End) < std::tie(C2.Begin, C2.End);
   }
 };
 
+template<>
+struct DenseMapInfo<Chunk> {
+  static inline Chunk getEmptyKey() {
+    return {DenseMapInfo<int>::getEmptyKey(),
+            DenseMapInfo<int>::getEmptyKey()};
+  }
+
+  static inline Chunk getTombstoneKey() {
+    return {DenseMapInfo<int>::getTombstoneKey(),
+            DenseMapInfo<int>::getTombstoneKey()};
+  }
+
+  static unsigned getHashValue(const Chunk Val) {
+    std::pair<int, int> PairVal = std::make_pair(Val.Begin, Val.End);
+    return DenseMapInfo<std::pair<int, int>>::getHashValue(PairVal);
+  }
+
+  static bool isEqual(const Chunk LHS, const Chunk RHS) {
+    return LHS == RHS;
+  }
+};
+
+
 /// Provides opaque interface for querying into ChunksToKeep without having to
 /// actually understand what is going on.
 class Oracle {