Re: Possible ANSI C Optimisation Done in Practice?

        For the case given, an optimizing compiler could perform the
optimization of calling the strlen function only once. This optimization
could be in done, with the following difficulties:


        1) The compiler needs to know the strlen is a standard function and that
its return value is based sole on its argument.
        2) The compiler also has to realize that the pointer s does not change.
        3) The compiler has to recognize that the contents of the string pointed
to by s does not change. To due this, it must recognize that t points to tmp
and s does not point to s. This is not so easy to implement.




                                                                                                Robert Sherry


"Ralph Corderoy" <ralph@inputplus.demon.co.uk> wrote in message
> [ can a C compiler optimize strlen(s) out of a loop? ]

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