Recover nestedloop regression reported by nightly tester.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51110 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/opt/opt.cpp b/tools/opt/opt.cpp
index 301a059..e3ea59e 100644
--- a/tools/opt/opt.cpp
+++ b/tools/opt/opt.cpp
@@ -280,6 +280,8 @@
   addPass(PM, createLICMPass());                 // Hoist loop invariants
   addPass(PM, createLoopUnswitchPass());         // Unswitch loops.
   addPass(PM, createLoopIndexSplitPass());       // Index split loops.
+  // FIXME : Removing instcombine causes nestedloop regression.
+  addPass(PM, createInstructionCombiningPass()); 
   addPass(PM, createIndVarSimplifyPass());       // Canonicalize indvars
   addPass(PM, createLoopDeletionPass());         // Delete dead loops
   addPass(PM, createLoopUnrollPass());           // Unroll small loops