Make MDNode use CallbackVH. Also change MDNode to store Value* instead of
Constant* in preperation of a future change to support holding non-Constants
in an MDNode.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71407 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Feature/embeddedmetadata.ll b/test/Feature/embeddedmetadata.ll
index 6f16e6a..c143398 100644
--- a/test/Feature/embeddedmetadata.ll
+++ b/test/Feature/embeddedmetadata.ll
@@ -2,7 +2,7 @@
 
 declare i8 @llvm.something({ } %a)
 
-@llvm.foo = internal constant { } !{i17 123, { } !"foobar"}
+@llvm.foo = internal constant { } !{i17 123, null, { } !"foobar"}
 
 define void @foo() {
   %x = call i8 @llvm.something({ } !{{ } !"f\00oa", i42 123})