Index: include/clang/Sema/Sema.h
===================================================================
--- include/clang/Sema/Sema.h
+++ include/clang/Sema/Sema.h
@@ -5166,6 +5166,11 @@
                          SourceRange DirectInitRange,
                          Expr *Initializer);
 
+  /// Produce diagnostics if FD is an aligned allocation or deallocation
+  /// function that is unavailable.
+  void diagnoseUnavailableAlignedAllocation(const FunctionDecl &FD,
+                                            SourceLocation Loc);
+
   bool CheckAllocatedType(QualType AllocType, SourceLocation Loc,
                           SourceRange R);
 
Index: lib/Sema/SemaDeclCXX.cpp
===================================================================
--- lib/Sema/SemaDeclCXX.cpp
+++ lib/Sema/SemaDeclCXX.cpp
@@ -8186,6 +8186,7 @@
         }
       }
 
+      DiagnoseUseOfDecl(OperatorDelete, Loc);
       MarkFunctionReferenced(Loc, OperatorDelete);
       Destructor->setOperatorDelete(OperatorDelete, ThisArg);
     }
Index: lib/Sema/SemaExpr.cpp
===================================================================
--- lib/Sema/SemaExpr.cpp
+++ lib/Sema/SemaExpr.cpp
@@ -226,6 +226,8 @@
     //   The function 'main' shall not be used within a program.
     if (cast<FunctionDecl>(D)->isMain())
       Diag(Loc, diag::ext_main_used);
+
+    diagnoseUnavailableAlignedAllocation(*cast<FunctionDecl>(D), Loc);
   }
 
   // See if this is an auto-typed variable whose initializer we are parsing.
Index: lib/Sema/SemaExprCXX.cpp
===================================================================
--- lib/Sema/SemaExprCXX.cpp
+++ lib/Sema/SemaExprCXX.cpp
@@ -1681,10 +1681,9 @@
 
 // Emit a diagnostic if an aligned allocation/deallocation function that is not
 // implemented in the standard library is selected.
-static void diagnoseUnavailableAlignedAllocation(const FunctionDecl &FD,
-                                                 SourceLocation Loc, bool IsDelete,
-                                                 Sema &S) {
-  if (!S.getLangOpts().AlignedAllocationUnavailable)
+void Sema::diagnoseUnavailableAlignedAllocation(const FunctionDecl &FD,
+                                                SourceLocation Loc) {
+  if (!getLangOpts().AlignedAllocationUnavailable)
     return;
 
   // Return if there is a definition.
@@ -1693,14 +1692,15 @@
 
   bool IsAligned = false;
   if (FD.isReplaceableGlobalAllocationFunction(&IsAligned) && IsAligned) {
-    const llvm::Triple &T = S.getASTContext().getTargetInfo().getTriple();
+    const llvm::Triple &T = getASTContext().getTargetInfo().getTriple();
     StringRef OSName = AvailabilityAttr::getPlatformNameSourceSpelling(
-        S.getASTContext().getTargetInfo().getPlatformName());
-
-    S.Diag(Loc, diag::warn_aligned_allocation_unavailable)
+        getASTContext().getTargetInfo().getPlatformName());
+    OverloadedOperatorKind Kind = FD.getDeclName().getCXXOverloadedOperator();
+    bool IsDelete = Kind == OO_Delete || Kind == OO_Array_Delete;
+    Diag(Loc, diag::warn_aligned_allocation_unavailable)
          << IsDelete << FD.getType().getAsString() << OSName
          << alignedAllocMinVersion(T.getOS()).getAsString();
-    S.Diag(Loc, diag::note_silence_unligned_allocation_unavailable);
+    Diag(Loc, diag::note_silence_unligned_allocation_unavailable);
   }
 }
 
@@ -2091,13 +2091,11 @@
     if (DiagnoseUseOfDecl(OperatorNew, StartLoc))
       return ExprError();
     MarkFunctionReferenced(StartLoc, OperatorNew);
-    diagnoseUnavailableAlignedAllocation(*OperatorNew, StartLoc, false, *this);
   }
   if (OperatorDelete) {
     if (DiagnoseUseOfDecl(OperatorDelete, StartLoc))
       return ExprError();
     MarkFunctionReferenced(StartLoc, OperatorDelete);
-    diagnoseUnavailableAlignedAllocation(*OperatorDelete, StartLoc, true, *this);
   }
 
   // C++0x [expr.new]p17:
@@ -3329,8 +3327,7 @@
       }
     }
 
-    diagnoseUnavailableAlignedAllocation(*OperatorDelete, StartLoc, true,
-                                         *this);
+    DiagnoseUseOfDecl(OperatorDelete, StartLoc);
 
     // Convert the operand to the type of the first parameter of operator
     // delete. This is only necessary if we selected a destroying operator
@@ -3463,6 +3460,8 @@
     return ExprError();
   assert(OperatorNewOrDelete && "should be found");
 
+  DiagnoseUseOfDecl(OperatorNewOrDelete, TheCall->getExprLoc());
+
   TheCall->setType(OperatorNewOrDelete->getReturnType());
   for (unsigned i = 0; i != TheCall->getNumArgs(); ++i) {
     QualType ParamTy = OperatorNewOrDelete->getParamDecl(i)->getType();
Index: test/CXX/drs/dr2xx.cpp
===================================================================
--- test/CXX/drs/dr2xx.cpp
+++ test/CXX/drs/dr2xx.cpp
@@ -726,7 +726,7 @@
   };
   struct C {
     inline void operator delete(void*) __attribute__((unused));
-    virtual ~C() {}
+    virtual ~C() {} // expected-warning {{'operator delete' was marked unused but was used}}
   };
 
   struct D {
Index: test/SemaCUDA/call-host-fn-from-device.cu
===================================================================
--- test/SemaCUDA/call-host-fn-from-device.cu
+++ test/SemaCUDA/call-host-fn-from-device.cu
@@ -85,7 +85,7 @@
 }
 
 __host__ __device__ void class_specific_delete(T *t, U *u) {
-  delete t; // ok, call sized device delete even though host has preferable non-sized version
+  delete t; // expected-error {{reference to __host__ function 'operator delete' in __host__ __device__ function}}
   delete u; // ok, call non-sized HD delete rather than sized D delete
 }
 
Index: test/SemaCXX/unavailable_aligned_allocation.cpp
===================================================================
--- test/SemaCXX/unavailable_aligned_allocation.cpp
+++ test/SemaCXX/unavailable_aligned_allocation.cpp
@@ -124,7 +124,73 @@
 // expected-note@-20 2 {{if you supply your own aligned allocation functions}}
 #endif
 
-// No errors if user-defined aligned allocation functions are available.
+// Test that diagnostics are produced when an unavailable aligned deallocation
+// function is called from a deleting destructor.
+struct alignas(256) OveralignedS2 {
+  int a[4];
+  virtual ~OveralignedS2();
+};
+
+OveralignedS2::~OveralignedS2() {}
+
+#ifdef NO_ERRORS
+// expected-no-diagnostics
+#else
+#if defined(IOS)
+// expected-error@-6 {{aligned deallocation function of type 'void (void *, enum std::align_val_t) noexcept' is only available on iOS 11 or newer}}}
+// expected-note@-7 {{if you supply your own aligned allocation functions}}
+#elif defined(TVOS)
+// expected-error@-9 {{aligned deallocation function of type 'void (void *, enum std::align_val_t) noexcept' is only available on tvOS 11 or newer}}}
+// expected-note@-10 {{if you supply your own aligned allocation functions}}
+#elif defined(WATCHOS)
+// expected-error@-12 {{aligned deallocation function of type 'void (void *, enum std::align_val_t) noexcept' is only available on watchOS 4 or newer}}}
+// expected-note@-13 {{if you supply your own aligned allocation functions}}
+#else
+// expected-error@-15 {{aligned deallocation function of type 'void (void *, enum std::align_val_t) noexcept' is only available on macOS 10.13 or newer}}}
+// expected-note@-16 {{if you supply your own aligned allocation functions}}
+#endif
+#endif
+
+void testExplicitOperatorNewDelete() {
+  void *p = operator new(128);
+  operator delete(p);
+  p = operator new[](128);
+  operator delete[](p);
+  p = __builtin_operator_new(128);
+  __builtin_operator_delete(p);
+}
+
+void testExplicitOperatorNewDeleteOveraligned() {
+  void *p = operator new(128, (std::align_val_t)64);
+  operator delete(p, (std::align_val_t)64);
+  p = operator new[](128, (std::align_val_t)64);
+  operator delete[](p, (std::align_val_t)64);
+  p = __builtin_operator_new(128, (std::align_val_t)64);
+  __builtin_operator_delete(p, (std::align_val_t)64);
+}
+
+#ifdef NO_ERRORS
+// expected-no-diagnostics
+#else
+// expected-error@-11 {{aligned allocation function of type 'void *(unsigned long, enum std::align_val_t)' is only available on}}
+// expected-note@-12 {{if you supply your own aligned allocation functions}}
+
+// expected-error@-13 {{aligned deallocation function of type 'void (void *, enum std::align_val_t) noexcept' is only available on}}
+// expected-note@-14 {{if you supply your own aligned allocation functions}}
+
+// expected-error@-15 {{aligned allocation function of type 'void *(unsigned long, enum std::align_val_t)' is only available on}}
+// expected-note@-16 {{if you supply your own aligned allocation functions}}
+
+// expected-error@-17 {{aligned deallocation function of type 'void (void *, enum std::align_val_t) noexcept' is only available on}}
+// expected-note@-18 {{if you supply your own aligned allocation functions}}
+
+// expected-error@-19 {{aligned allocation function of type 'void *(unsigned long, enum std::align_val_t)' is only available on}}
+// expected-note@-20 {{if you supply your own aligned allocation functions}}
+
+// expected-error@-21 {{aligned deallocation function of type 'void (void *, enum std::align_val_t) noexcept' is only available on}}
+// expected-note@-22 {{if you supply your own aligned allocation functions}}
+#endif
+
 void *operator new(std::size_t __sz, std::align_val_t) {
   static char array[256];
   return &array;