🚀 go-pugleaf

In article <CEDMAN.90Nov14221934@lynx.ps.uci.edu> cedman@golem.ps.uci.edu (Carl Edman) writes:
>
>That e.g. memmove() functions which are really optimal are quite large
>might be true. But most of that complexity results from an analysis
>of the parameters and choosing the corresponding algorithm to deal
>...
>make up most of the code. But now imagine a C compiler which does
>the parameter analysis (as far as possible) at run time and only
>inserts the 'correct' routine for these parameter sets.
>
>I think you will have to admit that in this case you could have significant
>speedups and space savings.
>
>	 Carl Edman

--

    Uh huh, right.	movmem(s, d, len)

    Now, unless all the parameters are basically globals of known alignment
    AND the 'length' is a constant, the compiler will not be able to make
    any major assumptions about the copy.

    Basically, a movmem would have to use the same operational guidelines
    as a structural assignment for the compiler to be able to make any
    assumptions, and then you might as well use a structure / structure
    assignment rather than a movmem.

    Unless  you can find several optimizable examples that would be
    *WIDELY* used in random source code (at least as a percentage of
    movmem()s in the source code), my opinion will not change :-)

					    -Matt

    Matthew Dillon	    dillon@Overload.Berkeley.CA.US
    891 Regal Rd.	    uunet.uu.net!overload!dillon
    Berkeley, Ca. 94708
    USA