First implementation of allocation elimination in Hydrogen.

src/hydrogen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2898 matching lines @@
     return false;
   }
   Run<HRedundantPhiEliminationPhase>();
   if (!CheckArgumentsPhiUses()) {
     *bailout_reason = kUnsupportedPhiUseOfArguments;
     return false;
   }
 
   // Remove dead code and phis
   if (FLAG_dead_code_elimination) Run<HDeadCodeEliminationPhase>();
+
+  if (FLAG_use_escape_analysis) Run<HEscapeAnalysisPhase>();
+
   CollectPhis();
 
   if (has_osr()) osr()->FinishOsrValues();
 
   Run<HInferRepresentationPhase>();
 
   // Remove HSimulate instructions that have turned out not to be needed
   // after all by folding them into the following HSimulate.
   // This must happen after inferring representations.
   Run<HMergeRemovableSimulatesPhase>();
 
   Run<HMarkDeoptimizeOnUndefinedPhase>();
   Run<HRepresentationChangesPhase>();
 
   Run<HInferTypesPhase>();
 
   // Must be performed before canonicalization to ensure that Canonicalize
   // will not remove semantically meaningful ToInt32 operations e.g. BIT_OR with
   // zero.
   if (FLAG_opt_safe_uint32_operations) Run<HUint32AnalysisPhase>();
 
   if (FLAG_use_canonicalizing) Run<HCanonicalizePhase>();
 
-  if (FLAG_use_escape_analysis) Run<HEscapeAnalysisPhase>();
-
   if (FLAG_use_gvn) Run<HGlobalValueNumberingPhase>();
 
   if (FLAG_use_range) Run<HRangeAnalysisPhase>();
 
   Run<HComputeMinusZeroChecksPhase>();
 
   // Eliminate redundant stack checks on backwards branches.
   Run<HStackCheckEliminationPhase>();
 
   if (FLAG_array_bounds_checks_elimination) {
@@ skipping 6752 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal