Add another InstCombine pass after LoopUnroll.

This is to cleanup some redundency generated by LoopUnroll pass. Such redundency may not be cleaned up by existing passes after LoopUnroll.

Differential Revision: http://reviews.llvm.org/D9777

llvm-svn: 237395

1 files changed, 3 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
index 94d419fc7f3..3b21d3f0cb1 100644
--- a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -382,6 +382,9 @@ void PassManagerBuilder::populateModulePassManager(
   if (!DisableUnrollLoops) {
     MPM.add(createLoopUnrollPass());    // Unroll small loops
 
+    // LoopUnroll may generate some redundency to cleanup.
+    MPM.add(createInstructionCombiningPass());
+
     // This is a barrier pass to avoid combine LICM pass and loop unroll pass
     // within same loop pass manager.
     MPM.add(createInstructionSimplifierPass());