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Re: a.out gives different results when compiled by g++ 3.1 and g++ 3.1 -O

From: Erick Alphonse <alphonse at lri dot fr>
To: Falk Hueffner <falk dot hueffner at student dot uni-tuebingen dot de>
Cc: gcc-bugs at gcc dot gnu dot org
Date: Sun, 16 Jun 2002 19:24:45 +0200
Subject: Re: a.out gives different results when compiled by g++ 3.1 and g++ 3.1 -O
References: <87bsac6y2s.fsf@student.uni-tuebingen.de>

Falk Hueffner wrote:

enum {N = 624,              // length of state vector
      M = 397,              // period parameter
      MAGIC = 0x9908B0DFU}; // magic constant

ui32 state[N];              // internal state
[...]
*p++ = twist( p[M-N], p[0], p[1] );

You're accessing out of the array bounds here, so anything might
happen.

Thanks a lot for your prompt answer!

I can't see the problem, the for-loop is entered N-1 times. Valgrind reported nothing wrong.

I don't understand, may you explain further?

Thanks for your help and time,
Regards,
Erick.

Follow-Ups:
- Re: a.out gives different results when compiled by g++ 3.1 and g++ 3.1 -O
  - From: Falk Hueffner

References:
- Re: a.out gives different results when compiled by g++ 3.1 and g++ 3.1 -O
  - From: Falk Hueffner

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