Add support to interchange loops with reductions.

This patch enables interchanging of tightly nested loops with reductions.
Differential Revision: http://reviews.llvm.org/D8314


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235571 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/IPO/PassManagerBuilder.cpp

@@ -246,9 +246,10 @@ void PassManagerBuilder::populateModulePassManager(
   MPM.add(createIndVarSimplifyPass());        // Canonicalize indvars
   MPM.add(createLoopIdiomPass());             // Recognize idioms like memset.
   MPM.add(createLoopDeletionPass());          // Delete dead loops
-  if (EnableLoopInterchange)
+  if (EnableLoopInterchange) {
     MPM.add(createLoopInterchangePass()); // Interchange loops
-
+    MPM.add(createCFGSimplificationPass());
+  }
   if (!DisableUnrollLoops)
     MPM.add(createSimpleLoopUnrollPass());    // Unroll small loops
   addExtensionsToPM(EP_LoopOptimizerEnd, MPM);