Fix some of the strange CBE-only failures that happened last night.

llvm-svn: 12980
diff --git a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
index 8462945..9bc897f 100644
--- a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -386,6 +386,7 @@
 
   // Now that we know the largest of of the induction variables in this loop,
   // insert a canonical induction variable of the largest size.
+  LargestType = LargestType->getUnsignedVersion();
   Value *IndVar = Rewriter.GetOrInsertCanonicalInductionVariable(L,LargestType);
   ++NumInserted;
   Changed = true;