diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -1215,11 +1215,6 @@
     return Visit(E->getSubExpr(), T);
   }
 
-  llvm::Constant *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E,
-                                                QualType T) {
-    return Visit(E->getSubExpr(), T);
-  }
-
   llvm::Constant *EmitArrayInitialization(InitListExpr *ILE, QualType T) {
     auto *CAT = CGM.getContext().getAsConstantArrayType(ILE->getType());
     assert(CAT && "can't emit array init for non-constant-bound array");
@@ -1279,6 +1274,10 @@
     if (ILE->isTransparent())
       return Visit(ILE->getInit(0), T);
 
+    for (Expr *E : ILE->inits())
+      if (isa<MaterializeTemporaryExpr>(E))
+        return nullptr;
+
     if (ILE->getType()->isArrayType())
       return EmitArrayInitialization(ILE, T);
 
@@ -1322,7 +1321,12 @@
       assert(CGM.getContext().hasSameUnqualifiedType(Ty, Arg->getType()) &&
              "argument to copy ctor is of wrong type");
 
-      return Visit(Arg, Ty);
+      // Look through the temporary; it's just converting the value to an
+      // lvalue to pass it to the constructor.
+      if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(Arg))
+        return Visit(MTE->getSubExpr(), Ty);
+      // Don't try to support arbitrary lvalue-to-rvalue conversions for now.
+      return nullptr;
     }
 
     return CGM.EmitNullConstant(Ty);
@@ -1654,12 +1658,8 @@
   InConstantContext = D.hasConstantInitialization();
 
   QualType destType = D.getType();
-
-  // Try to emit the initializer.  Note that this can allow some things that
-  // are not allowed by tryEmitPrivateForMemory alone.
-  if (auto value = D.evaluateValue()) {
-    return tryEmitPrivateForMemory(*value, destType);
-  }
+  const Expr *E = D.getInit();
+  assert(E && "No initializer to emit");
 
   // FIXME: Implement C++11 [basic.start.init]p2: if the initializer of a
   // reference is a constant expression, and the reference binds to a temporary,
@@ -1667,16 +1667,19 @@
   // incorrectly emit a prvalue constant in this case, and the calling code
   // interprets that as the (pointer) value of the reference, rather than the
   // desired value of the referee.
-  if (destType->isReferenceType())
-    return nullptr;
+  if (!destType->isLValueReferenceType()) {
+    QualType nonMemoryDestType = getNonMemoryType(CGM, destType);
+    if (llvm::Constant *C = ConstExprEmitter(*this).Visit(const_cast<Expr *>(E),
+                                                          nonMemoryDestType))
+      return emitForMemory(C, destType);
+  }
 
-  const Expr *E = D.getInit();
-  assert(E && "No initializer to emit");
+  // Try to emit the initializer.  Note that this can allow some things that
+  // are not allowed by tryEmitPrivateForMemory alone.
+  if (APValue *value = D.evaluateValue())
+    return tryEmitPrivateForMemory(*value, destType);
 
-  auto nonMemoryDestType = getNonMemoryType(CGM, destType);
-  auto C =
-    ConstExprEmitter(*this).Visit(const_cast<Expr*>(E), nonMemoryDestType);
-  return (C ? emitForMemory(C, destType) : nullptr);
+  return nullptr;
 }
 
 llvm::Constant *
@@ -1743,6 +1746,10 @@
                                                 QualType destType) {
   assert(!destType->isVoidType() && "can't emit a void constant");
 
+  if (llvm::Constant *C =
+          ConstExprEmitter(*this).Visit(const_cast<Expr *>(E), destType))
+    return C;
+
   Expr::EvalResult Result;
 
   bool Success = false;
@@ -1752,13 +1759,10 @@
   else
     Success = E->EvaluateAsRValue(Result, CGM.getContext(), InConstantContext);
 
-  llvm::Constant *C;
   if (Success && !Result.HasSideEffects)
-    C = tryEmitPrivate(Result.Val, destType);
-  else
-    C = ConstExprEmitter(*this).Visit(const_cast<Expr*>(E), destType);
+    return tryEmitPrivate(Result.Val, destType);
 
-  return C;
+  return nullptr;
 }
 
 llvm::Constant *CodeGenModule::getNullPointer(llvm::PointerType *T, QualType QT) {
diff --git a/clang/test/CodeGenCXX/const-init-cxx11.cpp b/clang/test/CodeGenCXX/const-init-cxx11.cpp
--- a/clang/test/CodeGenCXX/const-init-cxx11.cpp
+++ b/clang/test/CodeGenCXX/const-init-cxx11.cpp
@@ -88,7 +88,7 @@
 
   struct E {};
   struct Test2 : X<E,0>, X<E,1>, X<E,2>, X<E,3> {};
-  // CHECK: @_ZN9BaseClass2t2E ={{.*}} constant {{.*}} undef
+  // CHECK: @_ZN9BaseClass2t2E ={{.*}} constant {{.*}} zeroinitializer, align 1
   extern constexpr Test2 t2 = Test2();
 
   struct __attribute((packed)) PackedD { double y = 2; };
diff --git a/clang/test/CodeGenCXX/const-init-cxx1y.cpp b/clang/test/CodeGenCXX/const-init-cxx1y.cpp
--- a/clang/test/CodeGenCXX/const-init-cxx1y.cpp
+++ b/clang/test/CodeGenCXX/const-init-cxx1y.cpp
@@ -34,8 +34,8 @@
   // 'c.temporary', not the value as modified by the partial evaluation within
   // the initialization of 'c.x'.
   A c = { 10, (++c.temporary, b.x) };
-  // CHECK: @_ZGRN21ModifyStaticTemporary1cE_ = internal global i32 10
   // CHECK: @_ZN21ModifyStaticTemporary1cE ={{.*}} global {{.*}} zeroinitializer
+  // CHECK: @_ZGRN21ModifyStaticTemporary1cE_ = internal global i32 10
 }
 
 // CHECK: @_ZGRN28VariableTemplateWithConstRef1iIvEE_ = linkonce_odr constant i32 5, align 4
diff --git a/clang/test/CodeGenOpenCL/amdgpu-nullptr.cl b/clang/test/CodeGenOpenCL/amdgpu-nullptr.cl
--- a/clang/test/CodeGenOpenCL/amdgpu-nullptr.cl
+++ b/clang/test/CodeGenOpenCL/amdgpu-nullptr.cl
@@ -57,7 +57,7 @@
 // CHECK: @fold_generic ={{.*}} local_unnamed_addr addrspace(1) global ptr null, align 8
 generic int *fold_generic = (global int*)(generic float*)(private char*)0;
 
-// CHECK: @fold_priv ={{.*}} local_unnamed_addr addrspace(1) global ptr addrspace(5) addrspacecast (ptr null to ptr addrspace(5)), align 4
+// CHECK: @fold_priv ={{.*}} local_unnamed_addr addrspace(1) global ptr addrspace(5) addrspacecast (ptr addrspace(1) null to ptr addrspace(5)), align 4
 private short *fold_priv = (private short*)(generic int*)(global void*)0;
 
 // CHECK: @fold_priv_arith ={{.*}} local_unnamed_addr addrspace(1) global ptr addrspace(5) inttoptr (i32 9 to ptr addrspace(5)), align 4