Implement a variation of scalar replacement for non-escaping allocations.

runtime/vm/flow_graph_builder.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/flow_graph_builder.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/ast_printer.h"
 #include "vm/code_descriptors.h"
 #include "vm/dart_entry.h"
@@ skipping 274 matching lines @@
       callee_exit->AddDominatedBlock(block);
     }
     // The call block is now the immediate dominator of blocks whose
     // immediate dominator was the callee entry.
     call_block->ClearDominatedBlocks();
     for (intptr_t i = 0; i < callee_entry->dominated_blocks().length(); ++i) {
       BlockEntryInstr* block = callee_entry->dominated_blocks()[i];
       call_block->AddDominatedBlock(block);
     }
   }
+
+  // Neither call nor callee entry are in the graph at this point. Remove them
+  // from use lists.
+  callee_entry->UnuseAllInputs();
+  call_->UnuseAllInputs();
 }
 
 
 void EffectGraphVisitor::Append(const EffectGraphVisitor& other_fragment) {
   ASSERT(is_open());
   if (other_fragment.is_empty()) return;
   if (is_empty()) {
     entry_ = other_fragment.entry();
     exit_ = other_fragment.exit();
   } else {
@@ skipping 3077 matching lines @@
   intptr_t len = OS::SNPrint(NULL, 0, kFormat, function_name, reason) + 1;
   char* chars = Isolate::Current()->current_zone()->Alloc<char>(len);
   OS::SNPrint(chars, len, kFormat, function_name, reason);
   const Error& error = Error::Handle(
       LanguageError::New(String::Handle(String::New(chars))));
   Isolate::Current()->long_jump_base()->Jump(1, error);
 }
 
 
 }  // namespace dart