Re-land the fix for PR7139.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@104446 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index 17d85dc..d67618b 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -1856,7 +1856,7 @@
                                               const CXXZeroInitValueExpr *E) {
   QualType Ty = E->getType();
   LValue LV = LValue::MakeAddr(CreateMemTemp(Ty), MakeQualifiers(Ty));
-  EmitMemSetToZero(LV.getAddress(), Ty);
+  EmitNullInitialization(LV.getAddress(), Ty);
   return LV;
 }