When possible, move __block variables to the heap rather than copying them.

Fixes <rdar://problem/13330126>.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@176663 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 82d216e..4fa7905 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -7811,10 +7811,10 @@
     if (type->isStructureOrClassType()) {
       SourceLocation poi = var->getLocation();
       Expr *varRef =new (Context) DeclRefExpr(var, false, type, VK_LValue, poi);
-      ExprResult result =
-        PerformCopyInitialization(
-                        InitializedEntity::InitializeBlock(poi, type, false),
-                                  poi, Owned(varRef));
+      ExprResult result
+        = PerformMoveOrCopyInitialization(
+            InitializedEntity::InitializeBlock(poi, type, false),
+            var, var->getType(), varRef, /*AllowNRVO=*/true);
       if (!result.isInvalid()) {
         result = MaybeCreateExprWithCleanups(result);
         Expr *init = result.takeAs<Expr>();