Turn redundant phi elimination into proper HPhase.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 5cc5e80e25e354d368c08cbe7594e6b0164c3431..52de326dbc329290f63dfe7aeb4d71d5e29bc2bf 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -40,6 +40,7 @@
 #include "hydrogen-gvn.h"
 #include "hydrogen-osr.h"
 #include "hydrogen-range-analysis.h"
+#include "hydrogen-redundant-phi.h"
 #include "hydrogen-sce.h"
 #include "hydrogen-uint32-analysis.h"
 #include "lithium-allocator.h"
@@ -2523,53 +2524,6 @@ void HGraph::NullifyUnreachableInstructions() {
 }
 
 
-// Replace all phis consisting of a single non-loop operand plus any number of
-// loop operands by that single non-loop operand.
-void HGraph::EliminateRedundantPhis() {
-  HPhase phase("H_Redundant phi elimination", this);
-
-  // We do a simple fixed point iteration without any work list, because
-  // machine-generated JavaScript can lead to a very dense Hydrogen graph with
-  // an enormous work list and will consequently result in OOM. Experiments
-  // showed that this simple algorithm is good enough, and even e.g. tracking
-  // the set or range of blocks to consider is not a real improvement.
-  bool need_another_iteration;
-  ZoneList<HPhi*> redundant_phis(blocks_.length(), zone());
-  do {
-    need_another_iteration = false;
-    for (int i = 0; i < blocks_.length(); ++i) {
-      HBasicBlock* block = blocks_[i];
-      for (int j = 0; j < block->phis()->length(); j++) {
-        HPhi* phi = block->phis()->at(j);
-        HValue* replacement = phi->GetRedundantReplacement();
-        if (replacement != NULL) {
-          // Remember phi to avoid concurrent modification of the block's phis.
-          redundant_phis.Add(phi, zone());
-          for (HUseIterator it(phi->uses()); !it.Done(); it.Advance()) {
-            HValue* value = it.value();
-            value->SetOperandAt(it.index(), replacement);
-            need_another_iteration |= value->IsPhi();
-          }
-        }
-      }
-      for (int i = 0; i < redundant_phis.length(); i++) {
-        block->RemovePhi(redundant_phis[i]);
-      }
-      redundant_phis.Clear();
-    }
-  } while (need_another_iteration);
-
-#if DEBUG
-  // Make sure that we *really* removed all redundant phis.
-  for (int i = 0; i < blocks_.length(); ++i) {
-    for (int j = 0; j < blocks_[i]->phis()->length(); j++) {
-      ASSERT(blocks_[i]->phis()->at(j)->GetRedundantReplacement() == NULL);
-    }
-  }
-#endif
-}
-
-
 bool HGraph::CheckArgumentsPhiUses() {
   int block_count = blocks_.length();
   for (int i = 0; i < block_count; ++i) {
@@ -3417,7 +3371,7 @@ bool HGraph::Optimize(SmartArrayPointer<char>* bailout_reason) {
         "Unsupported phi use of const variable"));
     return false;
   }
-  EliminateRedundantPhis();
+  Run<HRedundantPhiEliminationPhase>();
   if (!CheckArgumentsPhiUses()) {
     *bailout_reason = SmartArrayPointer<char>(StrDup(
         "Unsupported phi use of arguments"));