diff --git a/libcxx/src/new.cpp b/libcxx/src/new.cpp
--- a/libcxx/src/new.cpp
+++ b/libcxx/src/new.cpp
@@ -73,32 +73,22 @@
         if (nh)
             nh();
         else
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
-            throw std::bad_alloc();
-#else
-            break;
-#endif
+            std::__throw_bad_alloc();
     }
     return p;
 }
 
 _LIBCPP_WEAK
-void*
-operator new(size_t size, const std::nothrow_t&) noexcept
-{
-    void* p = nullptr;
+void* operator new(size_t size, const std::nothrow_t&) noexcept {
 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
-    try
-    {
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
-        p = ::operator new(size);
+    try {
+#endif
+        return ::operator new(size);
 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+    } catch (...) {
+        return nullptr;
     }
-    catch (...)
-    {
-    }
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
-    return p;
+#endif
 }
 
 _LIBCPP_WEAK
@@ -109,22 +99,16 @@
 }
 
 _LIBCPP_WEAK
-void*
-operator new[](size_t size, const std::nothrow_t&) noexcept
-{
-    void* p = nullptr;
+void* operator new[](size_t size, const std::nothrow_t&) noexcept {
 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
-    try
-    {
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
-        p = ::operator new[](size);
+    try {
+#endif
+        return ::operator new[](size);
 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+    } catch (...) {
+        return nulltpr;
     }
-    catch (...)
-    {
-    }
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
-    return p;
+#endif
 }
 
 _LIBCPP_WEAK
@@ -192,34 +176,23 @@
         std::new_handler nh = std::get_new_handler();
         if (nh)
             nh();
-        else {
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
-            throw std::bad_alloc();
-#else
-            break;
-#endif
-        }
+        else
+            std::__throw_bad_alloc();
     }
     return p;
 }
 
 _LIBCPP_WEAK
-void*
-operator new(size_t size, std::align_val_t alignment, const std::nothrow_t&) noexcept
-{
-    void* p = nullptr;
+void* operator new(size_t size, std::align_val_t alignment, const std::nothrow_t&) noexcept {
 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
-    try
-    {
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
-        p = ::operator new(size, alignment);
+    try {
+#endif
+        return ::operator new(size, alignment);
 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+    } catch (...) {
+        return nullptr;
     }
-    catch (...)
-    {
-    }
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
-    return p;
+#endif
 }
 
 _LIBCPP_WEAK
@@ -230,22 +203,16 @@
 }
 
 _LIBCPP_WEAK
-void*
-operator new[](size_t size, std::align_val_t alignment, const std::nothrow_t&) noexcept
-{
-    void* p = nullptr;
+void* operator new[](size_t size, std::align_val_t alignment, const std::nothrow_t&) noexcept {
 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
-    try
-    {
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
-        p = ::operator new[](size, alignment);
+    try {
+#endif
+        return ::operator new[](size, alignment);
 #ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+    } catch (...) {
+        return nullptr;
     }
-    catch (...)
-    {
-    }
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
-    return p;
+#endif
 }
 
 _LIBCPP_WEAK
diff --git a/libcxx/test/libcxx/language.support/support.dynamic/new_dont_return_nullptr.pass.cpp b/libcxx/test/libcxx/language.support/support.dynamic/new_dont_return_nullptr.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/language.support/support.dynamic/new_dont_return_nullptr.pass.cpp
@@ -0,0 +1,37 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// void* operator new(std::size_t);
+// void* operator new(std::size_t, std::align_val_t);
+// void* operator new[](std::size_t);
+// void* operator new[](std::size_t, std::align_val_t);
+
+// This test ensures that we abort the program instead of returning nullptr
+// when we fail to satisfy the allocation request. The throwing versions of
+// `operator new` must never return nullptr on failure to allocate (per the
+// Standard) and the compiler actually relies on that for optimizations.
+// Returning nullptr from the throwing `operator new` can basically result
+// in miscompiles.
+
+// REQUIRES: has-unix-headers
+// REQUIRES: no-exceptions
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include <cstddef>
+#include <limits>
+#include <new>
+
+#include "check_assertion.h"
+
+int main(int, char**) {
+    EXPECT_DEATH((void)operator new(std::numeric_limits<std::size_t>::max()));
+    EXPECT_DEATH((void)operator new(std::numeric_limits<std::size_t>::max(), static_cast<std::align_val_t>(32)));
+    EXPECT_DEATH((void)operator new[](std::numeric_limits<std::size_t>::max()));
+    EXPECT_DEATH((void)operator new[](std::numeric_limits<std::size_t>::max(), static_cast<std::align_val_t>(32)));
+    return 0;
+}
diff --git a/libcxxabi/src/stdlib_new_delete.cpp b/libcxxabi/src/stdlib_new_delete.cpp
--- a/libcxxabi/src/stdlib_new_delete.cpp
+++ b/libcxxabi/src/stdlib_new_delete.cpp
@@ -17,6 +17,15 @@
 #error The _THROW_BAD_ALLOC and _LIBCXXABI_WEAK libc++ macros must \
        already be defined by libc++.
 #endif
+
+static void __throw_bad_alloc() {
+#ifndef _LIBCXXABI_NO_EXCEPTIONS
+    throw std::bad_alloc();
+#else
+    std::abort();
+#endif
+}
+
 // Implement all new and delete operators as weak definitions
 // in this shared library, so that they can be overridden by programs
 // that define non-weak copies of the functions.
@@ -36,32 +45,22 @@
         if (nh)
             nh();
         else
-#ifndef _LIBCXXABI_NO_EXCEPTIONS
-            throw std::bad_alloc();
-#else
-            break;
-#endif
+            __throw_bad_alloc();
     }
     return p;
 }
 
 _LIBCXXABI_WEAK
-void*
-operator new(size_t size, const std::nothrow_t&) noexcept
-{
-    void* p = nullptr;
+void* operator new(size_t size, const std::nothrow_t&) noexcept {
 #ifndef _LIBCXXABI_NO_EXCEPTIONS
-    try
-    {
-#endif // _LIBCXXABI_NO_EXCEPTIONS
-        p = ::operator new(size);
+    try {
+#endif
+        return ::operator new(size);
 #ifndef _LIBCXXABI_NO_EXCEPTIONS
+    } catch (...) {
+        return nullptr;
     }
-    catch (...)
-    {
-    }
-#endif // _LIBCXXABI_NO_EXCEPTIONS
-    return p;
+#endif
 }
 
 _LIBCXXABI_WEAK
@@ -72,22 +71,16 @@
 }
 
 _LIBCXXABI_WEAK
-void*
-operator new[](size_t size, const std::nothrow_t&) noexcept
-{
-    void* p = nullptr;
+void* operator new[](size_t size, const std::nothrow_t&) noexcept {
 #ifndef _LIBCXXABI_NO_EXCEPTIONS
-    try
-    {
-#endif // _LIBCXXABI_NO_EXCEPTIONS
-        p = ::operator new[](size);
+    try {
+#endif
+        return ::operator new[](size);
 #ifndef _LIBCXXABI_NO_EXCEPTIONS
+    } catch (...) {
+        return nullptr;
     }
-    catch (...)
-    {
-    }
-#endif // _LIBCXXABI_NO_EXCEPTIONS
-    return p;
+#endif
 }
 
 _LIBCXXABI_WEAK
@@ -155,34 +148,23 @@
         std::new_handler nh = std::get_new_handler();
         if (nh)
             nh();
-        else {
-#ifndef _LIBCXXABI_NO_EXCEPTIONS
-            throw std::bad_alloc();
-#else
-            break;
-#endif
-        }
+        else
+            __throw_bad_alloc();
     }
     return p;
 }
 
 _LIBCXXABI_WEAK
-void*
-operator new(size_t size, std::align_val_t alignment, const std::nothrow_t&) noexcept
-{
-    void* p = nullptr;
+void* operator new(size_t size, std::align_val_t alignment, const std::nothrow_t&) noexcept {
 #ifndef _LIBCXXABI_NO_EXCEPTIONS
-    try
-    {
-#endif // _LIBCXXABI_NO_EXCEPTIONS
-        p = ::operator new(size, alignment);
+    try {
+#endif
+        return ::operator new(size, alignment);
 #ifndef _LIBCXXABI_NO_EXCEPTIONS
+    } catch (...) {
+        return nullptr;
     }
-    catch (...)
-    {
-    }
-#endif // _LIBCXXABI_NO_EXCEPTIONS
-    return p;
+#endif
 }
 
 _LIBCXXABI_WEAK
@@ -193,22 +175,16 @@
 }
 
 _LIBCXXABI_WEAK
-void*
-operator new[](size_t size, std::align_val_t alignment, const std::nothrow_t&) noexcept
-{
-    void* p = nullptr;
+void* operator new[](size_t size, std::align_val_t alignment, const std::nothrow_t&) noexcept {
 #ifndef _LIBCXXABI_NO_EXCEPTIONS
-    try
-    {
-#endif // _LIBCXXABI_NO_EXCEPTIONS
-        p = ::operator new[](size, alignment);
+    try {
+#endif
+        return ::operator new[](size, alignment);
 #ifndef _LIBCXXABI_NO_EXCEPTIONS
+    } catch (...) {
+        return nullptr;
     }
-    catch (...)
-    {
-    }
-#endif // _LIBCXXABI_NO_EXCEPTIONS
-    return p;
+#endif
 }
 
 _LIBCXXABI_WEAK