diff --git a/llvm/include/llvm/ADT/DenseMap.h b/llvm/include/llvm/ADT/DenseMap.h
index f076049c55a26..d788d8e17e144 100644
--- a/llvm/include/llvm/ADT/DenseMap.h
+++ b/llvm/include/llvm/ADT/DenseMap.h
@@ -887,10 +887,8 @@ class SmallDenseMap
   AlignedCharArrayUnion<BucketT[InlineBuckets], LargeRep> storage;
 
 public:
-  explicit SmallDenseMap(unsigned NumInitBuckets = 0) {
-    if (NumInitBuckets > InlineBuckets)
-      NumInitBuckets = llvm::bit_ceil(NumInitBuckets);
-    init(NumInitBuckets);
+  explicit SmallDenseMap(unsigned NumElementsToReservre = 0) {
+    init(NumElementsToReservre);
   }
 
   SmallDenseMap(const SmallDenseMap &other) : BaseT() {
@@ -905,7 +903,7 @@ class SmallDenseMap
 
   template <typename InputIt>
   SmallDenseMap(const InputIt &I, const InputIt &E) {
-    init(NextPowerOf2(std::distance(I, E)));
+    init(std::distance(I, E));
     this->insert(I, E);
   }
 
@@ -1017,7 +1015,8 @@ class SmallDenseMap
     this->BaseT::copyFrom(other);
   }
 
-  void init(unsigned InitBuckets) {
+  void init(unsigned InitNumEntries) {
+    auto InitBuckets = BaseT::getMinBucketToReserveForEntries(InitNumEntries);
     Small = true;
     if (InitBuckets > InlineBuckets) {
       Small = false;
diff --git a/llvm/unittests/ADT/DenseMapTest.cpp b/llvm/unittests/ADT/DenseMapTest.cpp
index 785ab16271d93..50e9c6e138ef1 100644
--- a/llvm/unittests/ADT/DenseMapTest.cpp
+++ b/llvm/unittests/ADT/DenseMapTest.cpp
@@ -962,4 +962,73 @@ TEST(DenseMapCustomTest, PairPrinting) {
   EXPECT_EQ(R"({ (1, "one"), (2, "two") })", ::testing::PrintToString(Map));
 }
 
+TEST(DenseMapCustomTest, InitSize) {
+  constexpr unsigned ElemSize = sizeof(std::pair<int *, int>);
+
+  {
+    DenseMap<int *, int> Map;
+    EXPECT_EQ(ElemSize * 0U, Map.getMemorySize());
+  }
+  {
+    DenseMap<int *, int> Map(0);
+    EXPECT_EQ(ElemSize * 0U, Map.getMemorySize());
+  }
+  {
+    DenseMap<int *, int> Map(1);
+    EXPECT_EQ(ElemSize * 4U, Map.getMemorySize());
+  }
+  {
+    DenseMap<int *, int> Map(2);
+    EXPECT_EQ(ElemSize * 4U, Map.getMemorySize());
+  }
+  {
+    DenseMap<int *, int> Map(3);
+    EXPECT_EQ(ElemSize * 8U, Map.getMemorySize());
+  }
+  {
+    int A, B;
+    DenseMap<int *, int> Map = {{&A, 1}, {&B, 2}};
+    EXPECT_EQ(ElemSize * 4U, Map.getMemorySize());
+  }
+  {
+    int A, B, C;
+    DenseMap<int *, int> Map = {{&A, 1}, {&B, 2}, {&C, 3}};
+    EXPECT_EQ(ElemSize * 8U, Map.getMemorySize());
+  }
+}
+
+TEST(SmallDenseMapCustomTest, InitSize) {
+  constexpr unsigned ElemSize = sizeof(std::pair<int *, int>);
+  {
+    SmallDenseMap<int *, int> Map;
+    EXPECT_EQ(ElemSize * 4U, Map.getMemorySize());
+  }
+  {
+    SmallDenseMap<int *, int> Map(0);
+    EXPECT_EQ(ElemSize * 4U, Map.getMemorySize());
+  }
+  {
+    SmallDenseMap<int *, int> Map(1);
+    EXPECT_EQ(ElemSize * 4U, Map.getMemorySize());
+  }
+  {
+    SmallDenseMap<int *, int> Map(2);
+    EXPECT_EQ(ElemSize * 4U, Map.getMemorySize());
+  }
+  {
+    SmallDenseMap<int *, int> Map(3);
+    EXPECT_EQ(ElemSize * 8U, Map.getMemorySize());
+  }
+  {
+    int A, B;
+    SmallDenseMap<int *, int> Map = {{&A, 1}, {&B, 2}};
+    EXPECT_EQ(ElemSize * 4U, Map.getMemorySize());
+  }
+  {
+    int A, B, C;
+    SmallDenseMap<int *, int> Map = {{&A, 1}, {&B, 2}, {&C, 3}};
+    EXPECT_EQ(ElemSize * 8U, Map.getMemorySize());
+  }
+}
+
 } // namespace