Refactor Hydrogen GVN into an HPhase and use the phase zone.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index fdb5665ca16ec2604c54f44bb39f194eeeedfbee..4ae8d8195c41ab76171bd6c1c2c94da36e34c403 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -3946,21 +3946,6 @@ bool HOptimizedGraphBuilder::BuildGraph() {
 }
 
 
-// Perform common subexpression elimination and loop-invariant code motion.
-void HGraph::GlobalValueNumbering() {
-  HPhase phase("H_Global value numbering", this);
-  HGlobalValueNumberer gvn(this, info());
-  bool removed_side_effects = gvn.Analyze();
-  // Trigger a second analysis pass to further eliminate duplicate values that
-  // could only be discovered by removing side-effect-generating instructions
-  // during the first pass.
-  if (FLAG_smi_only_arrays && removed_side_effects) {
-    removed_side_effects = gvn.Analyze();
-    ASSERT(!removed_side_effects);
-  }
-}
-
-
 bool HGraph::Optimize(SmartArrayPointer<char>* bailout_reason) {
   *bailout_reason = SmartArrayPointer<char>();
   OrderBlocks();
@@ -4029,7 +4014,7 @@ bool HGraph::Optimize(SmartArrayPointer<char>* bailout_reason) {
 
   if (FLAG_use_canonicalizing) Canonicalize();
 
-  if (FLAG_use_gvn) GlobalValueNumbering();
+  if (FLAG_use_gvn) Run<HGlobalValueNumberingPhase>();
 
   if (FLAG_use_range) {
     HRangeAnalysis rangeAnalysis(this);
@@ -11554,7 +11539,22 @@ void HStatistics::SaveTiming(const char* name, int64_t ticks, unsigned size) {
 }
 
 
+HPhase::HPhase(const char* name, HGraph* graph, Zone* zone)
+    : CompilationPhase(name, graph->isolate(), zone), graph_(graph) {
+  if (FLAG_hydrogen_stats) {
+    graph_zone_start_allocation_size_ = graph->zone()->allocation_size();
+  }
+}
+
+
 HPhase::~HPhase() {
+  // Also count allocations in the graph's zone if it's not the phase zone
+  if (FLAG_hydrogen_stats && graph_->zone() != zone()) {
+    unsigned size =
+        graph_->zone()->allocation_size() - graph_zone_start_allocation_size_;
+    isolate()->GetHStatistics()->SaveTiming(name(), 0, size);
+  }
+
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }