Optimize redundant HCompareMap instructions with known successors.

src/hydrogen-instructions.cc

 // Copyright 2012 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 1099 matching lines @@
   }
   *block = NULL;
   return false;
 }
 
 
 void HCompareMap::PrintDataTo(StringStream* stream) {
   value()->PrintNameTo(stream);
   stream->Add(" (%p)", *map().handle());
   HControlInstruction::PrintDataTo(stream);
+  if (known_successor_index() == 0) {
+    stream->Add(" [true]");
+  } else if (known_successor_index() == 1) {
+    stream->Add(" [false]");
+  }
 }
 
 
 const char* HUnaryMathOperation::OpName() const {
   switch (op()) {
     case kMathFloor: return "floor";
     case kMathRound: return "round";
     case kMathAbs: return "abs";
     case kMathLog: return "log";
     case kMathExp: return "exp";
@@ skipping 3331 matching lines @@
       break;
     case kExternalMemory:
       stream->Add("[external-memory]");
       break;
   }
 
   stream->Add("@%d", offset());
 }
 
 } }  // namespace v8::internal