Index: llvm-convert.cpp
===================================================================
--- llvm-convert.cpp	(revision 122082)
+++ llvm-convert.cpp	(working copy)
@@ -4415,6 +4415,11 @@
   const Type *Ty = ConvertType(TREE_TYPE(exp));
   bool EltIsSigned = !TYPE_UNSIGNED(TREE_TYPE(TREE_OPERAND(exp, 0)));
   bool TyIsSigned = !TYPE_UNSIGNED(TREE_TYPE(exp));
+  
+  // If this is a structure-to-structure cast, just return the uncasted value.
+  if (!Elt->getType()->isFirstClassType() || !Ty->isFirstClassType())
+    return Elt;
+  
   // Elt and Ty can be integer, float or pointer here: need generalized cast
   Instruction::CastOps opcode = CastInst::getCastOpcode(Elt, EltIsSigned,
                                                         Ty, TyIsSigned);