From 89be05da5c7aee4645933ace1b1194642591d3a5 Mon Sep 17 00:00:00 2001
From: Fangrui Song <maskray@google.com>
Date: Fri, 1 May 2020 09:57:18 -0700
Subject: [PATCH] [ADT] Add DenseSetImpl(begin, end)

---
 include/llvm/ADT/DenseSet.h    | 6 ++++++
 unittests/ADT/DenseSetTest.cpp | 9 +++++++++
 2 files changed, 15 insertions(+)

diff --git a/include/llvm/ADT/DenseSet.h b/include/llvm/ADT/DenseSet.h
index 9afb715ae1d..07edc3d8e4e 100644
--- a/include/llvm/ADT/DenseSet.h
+++ b/include/llvm/ADT/DenseSet.h
@@ -66,6 +66,12 @@ public:
 
   explicit DenseSetImpl(unsigned InitialReserve = 0) : TheMap(InitialReserve) {}
 
+  template <typename InputIt>
+  DenseSetImpl(const InputIt &I, const InputIt &E)
+      : DenseSetImpl(PowerOf2Ceil(std::distance(I, E))) {
+    insert(I, E);
+  }
+
   DenseSetImpl(std::initializer_list<ValueT> Elems)
       : DenseSetImpl(PowerOf2Ceil(Elems.size())) {
     insert(Elems.begin(), Elems.end());
diff --git a/unittests/ADT/DenseSetTest.cpp b/unittests/ADT/DenseSetTest.cpp
index b080aa7f0c6..556bd46537d 100644
--- a/unittests/ADT/DenseSetTest.cpp
+++ b/unittests/ADT/DenseSetTest.cpp
@@ -70,6 +70,15 @@ typedef ::testing::Types<DenseSet<unsigned, TestDenseSetInfo>,
     DenseSetTestTypes;
 TYPED_TEST_CASE(DenseSetTest, DenseSetTestTypes);
 
+TYPED_TEST(DenseSetTest, Constructor) {
+  constexpr unsigned a[] = {1, 2, 4};
+  TypeParam set(std::begin(a), std::end(a));
+  EXPECT_EQ(3u, set.size());
+  EXPECT_EQ(1u, set.count(1));
+  EXPECT_EQ(1u, set.count(2));
+  EXPECT_EQ(1u, set.count(4));
+}
+
 TYPED_TEST(DenseSetTest, InitializerList) {
   TypeParam set({1, 2, 1, 4});
   EXPECT_EQ(3u, set.size());