Fix constant folding of %_IsMinusZero.

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 3127 matching lines @@
   ChangeRepresentation(value()->representation());
 }
 
 
 bool HCompareMinusZeroAndBranch::KnownSuccessorBlock(HBasicBlock** block) {
   if (FLAG_fold_constants && value()->IsConstant()) {
     HConstant* constant = HConstant::cast(value());
     if (constant->HasDoubleValue()) {
       *block = IsMinusZero(constant->DoubleValue())
           ? FirstSuccessor() : SecondSuccessor();
+      return true;
     }
-    return true;
   }
   if (value()->representation().IsSmiOrInteger32()) {
     // A Smi or Integer32 cannot contain minus zero.
     *block = SecondSuccessor();
     return true;
   }
   *block = NULL;
   return false;
 }
 
@@ skipping 1383 matching lines @@
       break;
     case kExternalMemory:
       stream->Add("[external-memory]");
       break;
   }
 
   stream->Add("@%d", offset());
 }
 
 } }  // namespace v8::internal