diff --git a/llvm/include/llvm/Support/Allocator.h b/llvm/include/llvm/Support/Allocator.h
--- a/llvm/include/llvm/Support/Allocator.h
+++ b/llvm/include/llvm/Support/Allocator.h
@@ -79,6 +79,11 @@
   BumpPtrAllocatorImpl(T &&Allocator)
       : AllocatorT(std::forward<T &&>(Allocator)) {}
 
+  // BumpPtrAllocator shouldn't be copyable. Explicitly delete this
+  // specialization of the perfect-forwarding constructor above.
+  template <typename AT, size_t SS, size_t ST, size_t GD>
+  BumpPtrAllocatorImpl(BumpPtrAllocatorImpl<AT, SS, ST, GD> &) = delete;
+
   // Manually implement a move constructor as we must clear the old allocator's
   // slabs as a matter of correctness.
   BumpPtrAllocatorImpl(BumpPtrAllocatorImpl &&Old)
diff --git a/llvm/unittests/Support/AllocatorTest.cpp b/llvm/unittests/Support/AllocatorTest.cpp
--- a/llvm/unittests/Support/AllocatorTest.cpp
+++ b/llvm/unittests/Support/AllocatorTest.cpp
@@ -9,6 +9,7 @@
 #include "llvm/Support/Allocator.h"
 #include "gtest/gtest.h"
 #include <cstdlib>
+#include <type_traits>
 
 using namespace llvm;
 
@@ -45,6 +46,16 @@
   EXPECT_EQ(1U, Alloc.GetNumSlabs());
 }
 
+TEST(AllocatorTest, NoCopy) {
+  constexpr bool CopyConstructible =
+      std::is_copy_constructible<BumpPtrAllocator>::value;
+  EXPECT_FALSE(CopyConstructible);
+
+  constexpr bool NonConstLRefConstructible =
+      std::is_constructible<BumpPtrAllocator, BumpPtrAllocator &>::value;
+  EXPECT_FALSE(NonConstLRefConstructible);
+}
+
 // Allocate enough bytes to create three slabs.
 TEST(AllocatorTest, ThreeSlabs) {
   BumpPtrAllocator Alloc;