Re: array index checking optimizations?

Bill Leonard writes
[deleted]
: If the bounds are compile-time constants (unlikely for array
                                                                                        ^^^^^^^^^^^^^^^^^^
: arguments, at least in Ada), then I believe our compiler would
    ^^^^^^^^^^^^^^^^^^^^^^^^^^
: correctly eliminate the index tests, assuming that the initial value
: of 'i' is within bounds.


      I think you mean "for unconstrained array arguments". There's some
room for optimization on the calling side if the formal parameter type
is a constrained array type. The use of the strong typing of the Ada
language here is a good way to allow your compiler to perform some
smart optimization, the more information you provide it (by declaring
some "ranged" integer types and not simply predefined integer) the
better the code could be.


      The chapter 10, "Improving performance", of the Ada Quality & Style
provides an interesting discussion about these issues. It's freely
available in various format at the URL :


ftp://sw-eng.falls-church.va.us/public/AdaIC/docs/style-guide/95style/


      and hypertext at :


http://sw-eng.falls-church.va.us/AdaIC/docs/style-guide/95style/html/contents.html


-- Laurent Guerby, student at Telecom Bretagne (France), Team Ada.
-- http://www-eleves.enst-bretagne.fr/~guerby/ (GATO Project).
--

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