diff --git a/llvm/include/llvm/ADT/SmallVector.h b/llvm/include/llvm/ADT/SmallVector.h
--- a/llvm/include/llvm/ADT/SmallVector.h
+++ b/llvm/include/llvm/ADT/SmallVector.h
@@ -1286,6 +1286,15 @@
   return {std::begin(Range), std::end(Range)};
 }
 
+template <typename Out, unsigned Size, typename R>
+SmallVector<Out, Size> to_vector_of(R &&Range) {
+  return {std::begin(Range), std::end(Range)};
+}
+
+template <typename Out, typename R> SmallVector<Out> to_vector_of(R &&Range) {
+  return {std::begin(Range), std::end(Range)};
+}
+
 } // end namespace llvm
 
 namespace std {
diff --git a/llvm/unittests/ADT/SmallVectorTest.cpp b/llvm/unittests/ADT/SmallVectorTest.cpp
--- a/llvm/unittests/ADT/SmallVectorTest.cpp
+++ b/llvm/unittests/ADT/SmallVectorTest.cpp
@@ -862,14 +862,16 @@
 
 template <typename InvalidType> class DualSmallVectorsTest;
 
+template <typename T, unsigned N>
+constexpr unsigned NumBuiltinElts(const SmallVector<T, N> &) {
+  return N;
+}
+
 template <typename VectorT1, typename VectorT2>
 class DualSmallVectorsTest<std::pair<VectorT1, VectorT2>> : public SmallVectorTestBase {
 protected:
   VectorT1 theVector;
   VectorT2 otherVector;
-
-  template <typename T, unsigned N>
-  static unsigned NumBuiltinElts(const SmallVector<T, N>&) { return N; }
 };
 
 typedef ::testing::Types<
@@ -909,7 +911,7 @@
 
   // If the source vector (otherVector) was in small-mode, assert that we just
   // moved the data pointer over.
-  EXPECT_TRUE(this->NumBuiltinElts(this->otherVector) == 4 ||
+  EXPECT_TRUE(NumBuiltinElts(this->otherVector) == 4 ||
               this->theVector.data() == OrigDataPtr);
 
   // There shouldn't be any live objects any more.
@@ -1134,6 +1136,67 @@
   EXPECT_TRUE(makeArrayRef(V2).equals({4, 5, 3, 2}));
 }
 
+TEST(SmallVectorTest, ToVector) {
+  {
+    std::vector<char> v = {'a', 'b', 'c'};
+    auto Vector = to_vector<4>(v);
+    static_assert(NumBuiltinElts(Vector) == 4u,
+                  "Wrong built-in elements number");
+    ASSERT_EQ(3u, Vector.size());
+    for (size_t I = 0; I < v.size(); ++I) {
+      EXPECT_EQ(v[I], Vector[I]);
+    }
+  }
+  {
+    std::vector<char> v = {'a', 'b', 'c'};
+    auto Vector = to_vector(v);
+    static_assert(NumBuiltinElts(Vector) != 4u,
+                  "Wrong built-in elements number");
+    ASSERT_EQ(3u, Vector.size());
+    for (size_t I = 0; I < v.size(); ++I) {
+      EXPECT_EQ(v[I], Vector[I]);
+    }
+  }
+}
+
+struct To {
+  int Content;
+  friend bool operator==(const To &LHS, const To &RHS) {
+    return LHS.Content == RHS.Content;
+  }
+};
+
+class From {
+public:
+  From() = default;
+  From(To M) { T = M; }
+  operator To() const { return T; }
+
+private:
+  To T;
+};
+
+TEST(SmallVectorTest, ToVectorOf) {
+  To to1{1}, to2{2}, to3{3};
+  std::vector<From> StdVector = {From(to1), From(to2), From(to3)};
+  {
+    llvm::SmallVector<To> Vector = llvm::to_vector_of<To>(StdVector);
+
+    ASSERT_EQ(StdVector.size(), Vector.size());
+    for (size_t I = 0; I < StdVector.size(); ++I)
+      EXPECT_EQ(StdVector[I], Vector[I]);
+  }
+  {
+    auto Vector = llvm::to_vector_of<To, 4>(StdVector);
+
+    ASSERT_EQ(StdVector.size(), Vector.size());
+    static_assert(NumBuiltinElts(Vector) == 4u,
+                  "Wrong built-in elements number");
+    for (size_t I = 0; I < StdVector.size(); ++I)
+      EXPECT_EQ(StdVector[I], Vector[I]);
+  }
+}
+
 template <class VectorT>
 class SmallVectorReferenceInvalidationTest : public SmallVectorTestBase {
 protected:
@@ -1143,11 +1206,6 @@
 
   VectorT V;
 
-  template <typename T, unsigned N>
-  static unsigned NumBuiltinElts(const SmallVector<T, N> &) {
-    return N;
-  }
-
   template <class T> static bool isValueType() {
     return std::is_same<T, typename VectorT::value_type>::value;
   }
@@ -1173,7 +1231,7 @@
 TYPED_TEST(SmallVectorReferenceInvalidationTest, PushBack) {
   // Note: setup adds [1, 2, ...] to V until it's at capacity in small mode.
   auto &V = this->V;
-  int N = this->NumBuiltinElts(V);
+  int N = NumBuiltinElts(V);
 
   // Push back a reference to last element when growing from small storage.
   V.push_back(V.back());
@@ -1195,7 +1253,7 @@
 TYPED_TEST(SmallVectorReferenceInvalidationTest, PushBackMoved) {
   // Note: setup adds [1, 2, ...] to V until it's at capacity in small mode.
   auto &V = this->V;
-  int N = this->NumBuiltinElts(V);
+  int N = NumBuiltinElts(V);
 
   // Push back a reference to last element when growing from small storage.
   V.push_back(std::move(V.back()));
@@ -1224,7 +1282,7 @@
 TYPED_TEST(SmallVectorReferenceInvalidationTest, Resize) {
   auto &V = this->V;
   (void)V;
-  int N = this->NumBuiltinElts(V);
+  int N = NumBuiltinElts(V);
   V.resize(N + 1, V.back());
   EXPECT_EQ(N, V.back());
 
@@ -1239,7 +1297,7 @@
   auto &V = this->V;
   (void)V;
   V.append(1, V.back());
-  int N = this->NumBuiltinElts(V);
+  int N = NumBuiltinElts(V);
   EXPECT_EQ(N, V[N - 1]);
 
   // Append enough more elements that V will grow again. This tests growing
@@ -1257,7 +1315,7 @@
 #if !defined(NDEBUG) && GTEST_HAS_DEATH_TEST
   EXPECT_DEATH(V.append(V.begin(), V.begin() + 1), this->AssertionMessage);
 
-  ASSERT_EQ(3u, this->NumBuiltinElts(V));
+  ASSERT_EQ(3u, NumBuiltinElts(V));
   ASSERT_EQ(3u, V.size());
   V.pop_back();
   ASSERT_EQ(2u, V.size());
@@ -1272,7 +1330,7 @@
   // Note: setup adds [1, 2, ...] to V until it's at capacity in small mode.
   auto &V = this->V;
   (void)V;
-  int N = this->NumBuiltinElts(V);
+  int N = NumBuiltinElts(V);
   ASSERT_EQ(unsigned(N), V.size());
   ASSERT_EQ(unsigned(N), V.capacity());
 
@@ -1372,7 +1430,7 @@
 
   // Cover NumToInsert <= this->end() - I.
   V.insert(V.begin() + 1, 1, V.back());
-  int N = this->NumBuiltinElts(V);
+  int N = NumBuiltinElts(V);
   EXPECT_EQ(N, V[1]);
 
   // Cover NumToInsert > this->end() - I, inserting enough elements that V will
@@ -1392,7 +1450,7 @@
   EXPECT_DEATH(V.insert(V.begin(), V.begin(), V.begin() + 1),
                this->AssertionMessage);
 
-  ASSERT_EQ(3u, this->NumBuiltinElts(V));
+  ASSERT_EQ(3u, NumBuiltinElts(V));
   ASSERT_EQ(3u, V.size());
   V.pop_back();
   ASSERT_EQ(2u, V.size());
@@ -1406,7 +1464,7 @@
 TYPED_TEST(SmallVectorReferenceInvalidationTest, EmplaceBack) {
   // Note: setup adds [1, 2, ...] to V until it's at capacity in small mode.
   auto &V = this->V;
-  int N = this->NumBuiltinElts(V);
+  int N = NumBuiltinElts(V);
 
   // Push back a reference to last element when growing from small storage.
   V.emplace_back(V.back());
@@ -1435,11 +1493,6 @@
 
   VectorT V;
 
-  template <typename T, unsigned N>
-  static unsigned NumBuiltinElts(const SmallVector<T, N> &) {
-    return N;
-  }
-
   void SetUp() override {
     SmallVectorTestBase::SetUp();
 
@@ -1460,7 +1513,7 @@
 TYPED_TEST(SmallVectorInternalReferenceInvalidationTest, EmplaceBack) {
   // Note: setup adds [1, 2, ...] to V until it's at capacity in small mode.
   auto &V = this->V;
-  int N = this->NumBuiltinElts(V);
+  int N = NumBuiltinElts(V);
 
   // Push back a reference to last element when growing from small storage.
   V.emplace_back(V.back().first, V.back().second);