diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -2256,7 +2256,7 @@
 def fno_asm : Flag<["-"], "fno-asm">, Group<f_Group>;
 def fno_asynchronous_unwind_tables : Flag<["-"], "fno-asynchronous-unwind-tables">, Group<f_Group>;
 def fno_assume_sane_operator_new : Flag<["-"], "fno-assume-sane-operator-new">, Group<f_Group>,
-  HelpText<"Don't assume that C++'s global operator new can't alias any pointer">,
+  HelpText<"Don't assume that C++'s global operator new can't alias any pointer or access accessible memory">,
   Flags<[CC1Option]>, MarshallingInfoNegativeFlag<CodeGenOpts<"AssumeSaneOperatorNew">>;
 def fno_builtin : Flag<["-"], "fno-builtin">, Group<f_Group>, Flags<[CC1Option, CoreOption]>,
   HelpText<"Disable implicit builtin knowledge of functions">;
diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -2062,11 +2062,14 @@
       AddAttributesFromFunctionProtoType(
           getContext(), FuncAttrs, Fn->getType()->getAs<FunctionProtoType>());
       if (AttrOnCallSite && Fn->isReplaceableGlobalAllocationFunction()) {
-        // A sane operator new returns a non-aliasing pointer.
+        // A sane operator new returns a non-aliasing pointer and is
+        // inaccessiblememonly
         auto Kind = Fn->getDeclName().getCXXOverloadedOperator();
         if (getCodeGenOpts().AssumeSaneOperatorNew &&
-            (Kind == OO_New || Kind == OO_Array_New))
+            (Kind == OO_New || Kind == OO_Array_New)) {
           RetAttrs.addAttribute(llvm::Attribute::NoAlias);
+          FuncAttrs.addAttribute(llvm::Attribute::InacccessibleMemOnly);
+        }
       }
       const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Fn);
       const bool IsVirtualCall = MD && MD->isVirtual();