Enable loop index split pass.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41714 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/opt/opt.cpp b/tools/opt/opt.cpp
index 4eca308..e990c7f 100644
--- a/tools/opt/opt.cpp
+++ b/tools/opt/opt.cpp
@@ -277,6 +277,7 @@
   addPass(PM, createLoopRotatePass());
   addPass(PM, createLICMPass());                 // Hoist loop invariants
   addPass(PM, createLoopUnswitchPass());         // Unswitch loops.
+  addPass(PM, createLoopIndexSplitPass());       // Index split loops.
   addPass(PM, createInstructionCombiningPass()); // Clean up after LICM/reassoc
   addPass(PM, createIndVarSimplifyPass());       // Canonicalize indvars
   addPass(PM, createLoopUnrollPass());           // Unroll small loops