[CodeGen] Add a pass to fold null checks into nearby memory operations.

Summary:
This change adds an "ImplicitNullChecks" target dependent pass.  This
pass folds null checks into memory operation using the FAULTING_LOAD
pseudo-op introduced in previous patches.

Depends on D10197
Depends on D10199
Depends on D10200

Reviewers: reames, rnk, pgavlin, JosephTremoulet, atrick

Reviewed By: atrick

Subscribers: ab, JosephTremoulet, llvm-commits

Differential Revision: http://reviews.llvm.org/D10201

llvm-svn: 239743

1 files changed, 1 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/CodeGen.cpp b/llvm/lib/CodeGen/CodeGen.cpp
index 2c6eaf35a25..155c5ecec77 100644
--- a/llvm/lib/CodeGen/CodeGen.cpp
+++ b/llvm/lib/CodeGen/CodeGen.cpp
@@ -42,6 +42,7 @@ void llvm::initializeCodeGen(PassRegistry &Registry) {
   initializeMachineBlockPlacementPass(Registry);
   initializeMachineBlockPlacementStatsPass(Registry);
   initializeMachineCSEPass(Registry);
+  initializeImplicitNullChecksPass(Registry);
   initializeMachineCombinerPass(Registry);
   initializeMachineCopyPropagationPass(Registry);
   initializeMachineDominatorTreePass(Registry);