Index: libcxx/trunk/include/memory
===================================================================
--- libcxx/trunk/include/memory
+++ libcxx/trunk/include/memory
@@ -1609,10 +1609,16 @@
         _LIBCPP_INLINE_VISIBILITY
         static
         void
-        __construct_forward(allocator_type& __a, _Ptr __begin1, _Ptr __end1, _Ptr& __begin2)
+        __construct_forward_with_exception_guarantees(allocator_type& __a, _Ptr __begin1, _Ptr __end1, _Ptr& __begin2)
         {
             for (; __begin1 != __end1; ++__begin1, (void) ++__begin2)
-                construct(__a, _VSTD::__to_raw_pointer(__begin2), _VSTD::move_if_noexcept(*__begin1));
+              construct(__a, _VSTD::__to_raw_pointer(__begin2),
+#ifdef _LIBCPP_NO_EXCEPTIONS
+                        _VSTD::move(*__begin1)
+#else
+                        _VSTD::move_if_noexcept(*__begin1)
+#endif
+                        );
         }
 
     template <class _Tp>
@@ -1625,7 +1631,7 @@
              is_trivially_move_constructible<_Tp>::value,
             void
         >::type
-        __construct_forward(allocator_type&, _Tp* __begin1, _Tp* __end1, _Tp*& __begin2)
+        __construct_forward_with_exception_guarantees(allocator_type&, _Tp* __begin1, _Tp* __end1, _Tp*& __begin2)
         {
             ptrdiff_t _Np = __end1 - __begin1;
             if (_Np > 0)
@@ -1672,12 +1678,18 @@
         _LIBCPP_INLINE_VISIBILITY
         static
         void
-        __construct_backward(allocator_type& __a, _Ptr __begin1, _Ptr __end1, _Ptr& __end2)
+        __construct_backward_with_exception_guarantees(allocator_type& __a, _Ptr __begin1, _Ptr __end1, _Ptr& __end2)
         {
             while (__end1 != __begin1)
             {
-                construct(__a, _VSTD::__to_raw_pointer(__end2-1), _VSTD::move_if_noexcept(*--__end1));
-                --__end2;
+              construct(__a, _VSTD::__to_raw_pointer(__end2 - 1),
+#ifdef _LIBCPP_NO_EXCEPTIONS
+                        _VSTD::move(*--__end1)
+#else
+                        _VSTD::move_if_noexcept(*--__end1)
+#endif
+                        );
+              --__end2;
             }
         }
 
@@ -1691,7 +1703,7 @@
              is_trivially_move_constructible<_Tp>::value,
             void
         >::type
-        __construct_backward(allocator_type&, _Tp* __begin1, _Tp* __end1, _Tp*& __end2)
+        __construct_backward_with_exception_guarantees(allocator_type&, _Tp* __begin1, _Tp* __end1, _Tp*& __end2)
         {
             ptrdiff_t _Np = __end1 - __begin1;
             __end2 -= _Np;
Index: libcxx/trunk/include/vector
===================================================================
--- libcxx/trunk/include/vector
+++ libcxx/trunk/include/vector
@@ -948,7 +948,8 @@
 vector<_Tp, _Allocator>::__swap_out_circular_buffer(__split_buffer<value_type, allocator_type&>& __v)
 {
     __annotate_delete();
-    __alloc_traits::__construct_backward(this->__alloc(), this->__begin_, this->__end_, __v.__begin_);
+    __alloc_traits::__construct_backward_with_exception_guarantees(
+        this->__alloc(), this->__begin_, this->__end_, __v.__begin_);
     _VSTD::swap(this->__begin_, __v.__begin_);
     _VSTD::swap(this->__end_, __v.__end_);
     _VSTD::swap(this->__end_cap(), __v.__end_cap());
@@ -963,8 +964,10 @@
 {
     __annotate_delete();
     pointer __r = __v.__begin_;
-    __alloc_traits::__construct_backward(this->__alloc(), this->__begin_, __p, __v.__begin_);
-    __alloc_traits::__construct_forward(this->__alloc(), __p, this->__end_, __v.__end_);
+    __alloc_traits::__construct_backward_with_exception_guarantees(
+        this->__alloc(), this->__begin_, __p, __v.__begin_);
+    __alloc_traits::__construct_forward_with_exception_guarantees(
+        this->__alloc(), __p, this->__end_, __v.__end_);
     _VSTD::swap(this->__begin_, __v.__begin_);
     _VSTD::swap(this->__end_, __v.__end_);
     _VSTD::swap(this->__end_cap(), __v.__end_cap());
Index: libcxx/trunk/test/libcxx/containers/sequences/vector/exception_safety_exceptions_disabled.sh.cpp
===================================================================
--- libcxx/trunk/test/libcxx/containers/sequences/vector/exception_safety_exceptions_disabled.sh.cpp
+++ libcxx/trunk/test/libcxx/containers/sequences/vector/exception_safety_exceptions_disabled.sh.cpp
@@ -0,0 +1,57 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// RUN: %build -fno-exceptions
+// RUN: %run
+
+// UNSUPPORTED: c++98, c++03
+
+// <vector>
+
+// Test that vector always moves elements when exceptions are disabled.
+// vector is allowed to move or copy elements while resizing, so long as
+// it still provides the strong exception safety guarantee.
+
+#include <vector>
+#include <cassert>
+
+#include "test_macros.h"
+
+#ifndef TEST_HAS_NO_EXCEPTIONS
+#error exceptions should be disabled.
+#endif
+
+bool allow_moves = false;
+
+class A {
+public:
+  A() {}
+  A(A&&) { assert(allow_moves); }
+  explicit A(int) {}
+  A(A const&) { assert(false); }
+};
+
+int main(int, char**) {
+  std::vector<A> v;
+
+  // Create a vector containing some number of elements that will
+  // have to be moved when it is resized.
+  v.reserve(10);
+  size_t old_cap = v.capacity();
+  for (int i = 0; i < v.capacity(); ++i) {
+    v.emplace_back(42);
+  }
+  assert(v.capacity() == old_cap);
+  assert(v.size() == v.capacity());
+
+  // The next emplace back should resize.
+  allow_moves = true;
+  v.emplace_back(42);
+
+  return 0;
+}