several multiple-retval fixes for bugpoint.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50331 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/bugpoint/ExtractFunction.cpp b/tools/bugpoint/ExtractFunction.cpp
index 906826e..ca8a279 100644
--- a/tools/bugpoint/ExtractFunction.cpp
+++ b/tools/bugpoint/ExtractFunction.cpp
@@ -71,7 +71,9 @@
   Instruction *TheInst = RI;              // Got the corresponding instruction!
 
   // If this instruction produces a value, replace any users with null values
-  if (TheInst->getType() != Type::VoidTy)
+  if (isa<StructType>(TheInst->getType()))
+    TheInst->replaceAllUsesWith(UndefValue::get(TheInst->getType()));
+  else if (TheInst->getType() != Type::VoidTy)
     TheInst->replaceAllUsesWith(Constant::getNullValue(TheInst->getType()));
 
   // Remove the instruction from the program.