Add an optimization that does CSE in a group of similar GEPs.

This optimization merges the common part of a group of GEPs, so we can compute
each pointer address by adding a simple offset to the common part.

The optimization is currently only enabled for the NVPTX backend, where it has
a large payoff on some benchmarks.

Review: http://reviews.llvm.org/D3462

Patch by Jingyue Wu.

llvm-svn: 207783

1 files changed, 1 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Scalar/Scalar.cpp b/llvm/lib/Transforms/Scalar/Scalar.cpp
index 09167b9e82a..f8f828c8405 100644
--- a/llvm/lib/Transforms/Scalar/Scalar.cpp
+++ b/llvm/lib/Transforms/Scalar/Scalar.cpp
@@ -64,6 +64,7 @@ void llvm::initializeScalarOpts(PassRegistry &Registry) {
   initializeStructurizeCFGPass(Registry);
   initializeSinkingPass(Registry);
   initializeTailCallElimPass(Registry);
+  initializeSeparateConstOffsetFromGEPPass(Registry);
 }
 
 void LLVMInitializeScalarOpts(LLVMPassRegistryRef R) {