Implement global check elimination using the HFlowEngine.

BUG=
R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/46883009

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18137 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen-check-elimination.h

@@ -29,6 +29,7 @@
 #define V8_HYDROGEN_CHECK_ELIMINATION_H_
 
 #include "hydrogen.h"
+#include "hydrogen-alias-analysis.h"
 
 namespace v8 {
 namespace internal {
@@ -38,12 +39,33 @@ namespace internal {
 class HCheckEliminationPhase : public HPhase {
  public:
   explicit HCheckEliminationPhase(HGraph* graph)
-      : HPhase("H_Check Elimination", graph) { }
+    : HPhase("H_Check Elimination", graph),
+      aliasing_(),
+      redundant_(0),
+      removed_(0),
+      narrowed_(0),
+      loads_(0),
+      empty_(0),
+      compares_true_(0),
+      compares_false_(0),
+      transitions_(0) { }
 
   void Run();
 
+  friend class HCheckTable;
+
  private:
-  void EliminateLocalChecks(HBasicBlock* block);
+  void PrintStats();
+
+  HAliasAnalyzer* aliasing_;
+  int redundant_;
+  int removed_;
+  int narrowed_;
+  int loads_;
+  int empty_;
+  int compares_true_;
+  int compares_false_;
+  int transitions_;
 };
 
 

src/hydrogen.cc

@@ -3770,7 +3770,6 @@ bool HGraph::Optimize(BailoutReason* bailout_reason) {
   // where unreachable code could unnecessarily defeat LICM.
   Run<HMarkUnreachableBlocksPhase>();
 
-  if (FLAG_check_elimination) Run<HCheckEliminationPhase>();
   if (FLAG_dead_code_elimination) Run<HDeadCodeEliminationPhase>();
   if (FLAG_use_escape_analysis) Run<HEscapeAnalysisPhase>();
 
@@ -3801,6 +3800,8 @@ bool HGraph::Optimize(BailoutReason* bailout_reason) {
 
   if (FLAG_use_gvn) Run<HGlobalValueNumberingPhase>();
 
+  if (FLAG_check_elimination) Run<HCheckEliminationPhase>();
+
   if (FLAG_use_range) Run<HRangeAnalysisPhase>();
 
   Run<HComputeChangeUndefinedToNaN>();