Parallel fix to r88951: use TrackingVH to hold forward decl.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@88962 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index 7aa7201..41ffddd 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -490,6 +490,7 @@
   if (!Decl->getDefinition(M->getContext()))
     return FwdDecl;
 
+  llvm::TrackingVH<llvm::MDNode> FwdDeclNode = FwdDecl.getNode();
   // Otherwise, insert it into the TypeCache so that recursive uses will find
   // it.
   TypeCache[QualType(Ty, 0).getAsOpaquePtr()] = FwdDecl.getNode();
@@ -563,7 +564,7 @@
 
   // Now that we have a real decl for the struct, replace anything using the
   // old decl with the new one.  This will recursively update the debug info.
-  FwdDecl.replaceAllUsesWith(RealDecl);
+  llvm::DIDerivedType(FwdDeclNode).replaceAllUsesWith(RealDecl);
 
   return RealDecl;
 }