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From: Felipe Magno de Almeida (felipe.m.almeida_at_[hidden])
Date: 2005-10-03 15:43:10

On 10/3/05, Rob Stewart <stewart_at_[hidden]> wrote:
> (Note that __assume(false) is useless, for it is an expression
> that the optimizer cannot use to optimize anything. So, while I
> understand that you were trying to simplify things for the
> discussion, let's also not lose sight of what is really meant
> when writing __assume(false) in the above examples.)

I think you're wrong.
__assume(false) means that this code will never be executed, and as
such isnt useless for the optimizer.

  // do something here
  BOOST_LOG(dbg) << "Error! this code should never execute!" << std::endl;

tells the optimizer that the else will never be taken and that the
compiler can elide this and do not write the LOG code.
When you write
__assume(x != 0) it means to the optimizer that he can assume that x
will always be different from 0. When you write __assume(false) it
means that that place can never be reached.

   Felipe Magno de Almeida
Developer from synergy and Computer Science student from State
University of Campinas(UNICAMP).
"There is no dark side of the moon really. Matter of fact it's all dark."

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