Improve representation inference for HUnknownOSRValue.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 7cde43797dd0618c83b0e19a90aa43945f3ee5fd..3b7b37de374b622a6f13f27e40bcc296ef444c2e 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -2520,6 +2520,14 @@ HGraph* HGraphBuilder::CreateGraph() {
   if (FLAG_eliminate_dead_phis) graph()->EliminateUnreachablePhis();
   graph()->CollectPhis();
 
+  if (graph()->has_osr_loop_entry()) {
+    const ZoneList<HPhi*>* phis = graph()->osr_loop_entry()->phis();
+    for (int j = 0; j < phis->length(); j++) {
+      HPhi* phi = phis->at(j);
+      graph()->osr_values()->at(phi->merged_index())->set_incoming_value(phi);
+    }
+  }
+
   HInferRepresentation rep(graph());
   rep.Analyze();
 
@@ -3092,8 +3100,8 @@ bool HGraphBuilder::HasOsrEntryAt(IterationStatement* statement) {
 }
 
 
-void HGraphBuilder::PreProcessOsrEntry(IterationStatement* statement) {
-  if (!HasOsrEntryAt(statement)) return;
+bool HGraphBuilder::PreProcessOsrEntry(IterationStatement* statement) {
+  if (!HasOsrEntryAt(statement)) return false;
 
   HBasicBlock* non_osr_entry = graph()->CreateBasicBlock();
   HBasicBlock* osr_entry = graph()->CreateBasicBlock();
@@ -3108,10 +3116,14 @@ void HGraphBuilder::PreProcessOsrEntry(IterationStatement* statement) {
   int osr_entry_id = statement->OsrEntryId();
   int first_expression_index = environment()->first_expression_index();
   int length = environment()->length();
+  ZoneList<HUnknownOSRValue*>* osr_values =
+      new(zone()) ZoneList<HUnknownOSRValue*>(length);
+
   for (int i = 0; i < first_expression_index; ++i) {
     HUnknownOSRValue* osr_value = new(zone()) HUnknownOSRValue;
     AddInstruction(osr_value);
     environment()->Bind(i, osr_value);
+    osr_values->Add(osr_value);
   }
 
   if (first_expression_index != length) {
@@ -3120,9 +3132,12 @@ void HGraphBuilder::PreProcessOsrEntry(IterationStatement* statement) {
       HUnknownOSRValue* osr_value = new(zone()) HUnknownOSRValue;
       AddInstruction(osr_value);
       environment()->Push(osr_value);
+      osr_values->Add(osr_value);
     }
   }
 
+  graph()->set_osr_values(osr_values);
+
   AddSimulate(osr_entry_id);
   AddInstruction(new(zone()) HOsrEntry(osr_entry_id));
   HContext* context = new(zone()) HContext;
@@ -3131,6 +3146,7 @@ void HGraphBuilder::PreProcessOsrEntry(IterationStatement* statement) {
   current_block()->Goto(loop_predecessor);
   loop_predecessor->SetJoinId(statement->EntryId());
   set_current_block(loop_predecessor);
+  return true;
 }
 
 
@@ -3154,10 +3170,11 @@ void HGraphBuilder::VisitDoWhileStatement(DoWhileStatement* stmt) {
   ASSERT(current_block() != NULL);
   ASSERT(current_block()->HasPredecessor());
   ASSERT(current_block() != NULL);
-  PreProcessOsrEntry(stmt);
+  bool osr_entry = PreProcessOsrEntry(stmt);
   HBasicBlock* loop_entry = CreateLoopHeaderBlock();
   current_block()->Goto(loop_entry);
   set_current_block(loop_entry);
+  if (osr_entry) graph()->set_osr_loop_entry(loop_entry);
 
   BreakAndContinueInfo break_info(stmt);
   CHECK_BAILOUT(VisitLoopBody(stmt, loop_entry, &break_info));
@@ -3196,10 +3213,12 @@ void HGraphBuilder::VisitWhileStatement(WhileStatement* stmt) {
   ASSERT(current_block() != NULL);
   ASSERT(current_block()->HasPredecessor());
   ASSERT(current_block() != NULL);
-  PreProcessOsrEntry(stmt);
+  bool osr_entry = PreProcessOsrEntry(stmt);
   HBasicBlock* loop_entry = CreateLoopHeaderBlock();
   current_block()->Goto(loop_entry);
   set_current_block(loop_entry);
+  if (osr_entry) graph()->set_osr_loop_entry(loop_entry);
+
 
   // If the condition is constant true, do not generate a branch.
   HBasicBlock* loop_successor = NULL;
@@ -3241,10 +3260,11 @@ void HGraphBuilder::VisitForStatement(ForStatement* stmt) {
     CHECK_ALIVE(Visit(stmt->init()));
   }
   ASSERT(current_block() != NULL);
-  PreProcessOsrEntry(stmt);
+  bool osr_entry = PreProcessOsrEntry(stmt);
   HBasicBlock* loop_entry = CreateLoopHeaderBlock();
   current_block()->Goto(loop_entry);
   set_current_block(loop_entry);
+  if (osr_entry) graph()->set_osr_loop_entry(loop_entry);
 
   HBasicBlock* loop_successor = NULL;
   if (stmt->cond() != NULL) {
@@ -3336,10 +3356,11 @@ void HGraphBuilder::VisitForInStatement(ForInStatement* stmt) {
   HForInCacheArray::cast(array)->set_index_cache(
       HForInCacheArray::cast(index_cache));
 
-  PreProcessOsrEntry(stmt);
+  bool osr_entry = PreProcessOsrEntry(stmt);
   HBasicBlock* loop_entry = CreateLoopHeaderBlock();
   current_block()->Goto(loop_entry);
   set_current_block(loop_entry);
+  if (osr_entry) graph()->set_osr_loop_entry(loop_entry);
 
   HValue* index = environment()->ExpressionStackAt(0);
   HValue* limit = environment()->ExpressionStackAt(1);