[llvm] r257767 - [LTO] Add a run of LoopUnroll

[James Molloy via llvm-commits]

Author: jamesm
Date: Thu Jan 14 09:00:09 2016
New Revision: 257767

URL: http://llvm.org/viewvc/llvm-project?rev=257767&view=rev
Log:
[LTO] Add a run of LoopUnroll

Loop trip counts can often be resolved during LTO. We should obviously be unrolling small loops once those trip counts have been resolved, but we weren't.

Modified:
    llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp

Modified: llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp?rev=257767&r1=257766&r2=257767&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp Thu Jan 14 09:00:09 2016
@@ -573,7 +573,12 @@ void PassManagerBuilder::addLTOOptimizat
   if (EnableLoopInterchange)
     PM.add(createLoopInterchangePass());
 
+  if (!DisableUnrollLoops)
+    PM.add(createSimpleLoopUnrollPass());   // Unroll small loops
   PM.add(createLoopVectorizePass(true, LoopVectorize));
+  // The vectorizer may have significantly shortened a loop body; unroll again.
+  if (!DisableUnrollLoops)
+    PM.add(createLoopUnrollPass());
 
   // Now that we've optimized loops (in particular loop induction variables),
   // we may have exposed more scalar opportunities. Run parts of the scalar