Check comparison tag before checking attributes in IfThenElseInstr::AttributesEqual.

runtime/vm/intermediate_language.h

 // Copyright (c) 2013, 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.
 
 #ifndef VM_INTERMEDIATE_LANGUAGE_H_
 #define VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 3176 matching lines @@
   intptr_t if_true() const { return if_true_; }
   intptr_t if_false() const { return if_false_; }
 
   virtual bool AllowsCSE() const { return comparison()->AllowsCSE(); }
   virtual EffectSet Effects() const { return comparison()->Effects(); }
   virtual EffectSet Dependencies() const {
     return comparison()->Dependencies();
   }
   virtual bool AttributesEqual(Instruction* other) const {
     IfThenElseInstr* other_if_then_else = other->AsIfThenElse();
-    return comparison()->AttributesEqual(other_if_then_else->comparison()) &&
+    return (comparison()->tag() == other_if_then_else->comparison()->tag()) &&
+           comparison()->AttributesEqual(other_if_then_else->comparison()) &&
            (if_true_ == other_if_then_else->if_true_) &&
            (if_false_ == other_if_then_else->if_false_);
   }
 
   virtual bool MayThrow() const { return comparison()->MayThrow(); }
 
  private:
   virtual void RawSetInputAt(intptr_t i, Value* value) {
     comparison()->RawSetInputAt(i, value);
   }
@@ skipping 5007 matching lines @@
   LocationSummary* Name::MakeLocationSummary(Zone* zone, bool opt) const {    \
     UNIMPLEMENTED();                                                          \
     return NULL;                                                              \
   }                                                                           \
   void Name::EmitNativeCode(FlowGraphCompiler* compiler) { UNIMPLEMENTED(); }
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_