[PATCH] [LoopReroll] Run LICM before Loop Rerolling.

[James Molloy]

Hi Hal,

OK, I managed to track it down (bugpoint didn't help, but I strained my eyes over every pass until I'd worked it out :) ).

It comes from loop unrolling - we unroll part of a loop nest but don't run LICM afterwards to clean up. New patch adds it to the cleanup part of the scalar optimizer.

As this was a latent bug, I don't think we need to smarten up the reroller to handle this - we should be able to expect our input to be optimized. Do you agree with this?

Cheers,

James


REPOSITORY
  rL LLVM

http://reviews.llvm.org/D7674

Files:
  lib/Transforms/IPO/PassManagerBuilder.cpp

Index: lib/Transforms/IPO/PassManagerBuilder.cpp
===================================================================
--- lib/Transforms/IPO/PassManagerBuilder.cpp
+++ lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -259,6 +259,7 @@
   MPM.add(createJumpThreadingPass());         // Thread jumps
   MPM.add(createCorrelatedValuePropagationPass());
   MPM.add(createDeadStoreEliminationPass());  // Delete dead stores
+  MPM.add(createLICMPass());
 
   addExtensionsToPM(EP_ScalarOptimizerLate, MPM);

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