Define DEBUG for v8_optimized_debug=2

src/deoptimizer.h

 // 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 488 matching lines @@
 
   void SetFrameSlot(unsigned offset, intptr_t value) {
     *GetFrameSlotPointer(offset) = value;
   }
 
   void SetCallerPc(unsigned offset, intptr_t value);
 
   void SetCallerFp(unsigned offset, intptr_t value);
 
   intptr_t GetRegister(unsigned n) const {
-    ASSERT(n < ARRAY_SIZE(registers_));
+#if DEBUG
+    // This convoluted ASSERT is needed to work around a gcc problem that
+    // improperly detects an array bounds overflow in optimized debug builds
+    // when using a plain ASSERT.
+    if (n >= ARRAY_SIZE(registers_)) {
+      ASSERT(false);
+      return 0;
+    }
+#endif
     return registers_[n];
   }
 
   double GetDoubleRegister(unsigned n) const {
     ASSERT(n < ARRAY_SIZE(double_registers_));
     return double_registers_[n];
   }
 
   void SetRegister(unsigned n, intptr_t value) {
     ASSERT(n < ARRAY_SIZE(registers_));
@@ skipping 404 matching lines @@
   Object** expression_stack_;
   int source_position_;
 
   friend class Deoptimizer;
 };
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_DEOPTIMIZER_H_