Update various Loop optimization passes to cope with the possibility that
LoopSimplify form may not be available.

llvm-svn: 86175
diff --git a/llvm/lib/Transforms/Scalar/LoopIndexSplit.cpp b/llvm/lib/Transforms/Scalar/LoopIndexSplit.cpp
index 920d85c..8b6a233 100644
--- a/llvm/lib/Transforms/Scalar/LoopIndexSplit.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopIndexSplit.cpp
@@ -209,6 +209,10 @@
   L = IncomingLoop;
   LPM = &LPM_Ref;
 
+  // If LoopSimplify form is not available, stay out of trouble.
+  if (!L->isLoopSimplifyForm())
+    return false;
+
   // FIXME - Nested loops make dominator info updates tricky. 
   if (!L->getSubLoops().empty())
     return false;