Re: Help with research on optimization techniques

abacus@acaps.CS.McGill.CA (Hisham PETRY) writes:


> I am requesting some assistance in researching my project,
>"While to For loop conversion". The motivation for this transformation
>is the fact that McGill has several optimizations for For loops that
>don't exist for While loops.


Lots of people do this, for exactly the same reason.
Not many papers about it though. One that comes to mind is


    author="Randy Allen and Steve Johnson",
    title="Compiling {C} for Vectorization, Parallelization, and Inline
                                  Expansion",
    pages="241--249",
    journal=sigplan,
    year=1988,
    month=jul,
    volume=23,
    number=7,
    note=pldi88


>proofs of loop equivalence,
>showing that in fact While loops are equivalent to For loops.


Well, it's trivial in C.


while (p) x;


is exactly equivalent to


for(; p; ) x;


Of course, this probably isn't very helpful to your compiler. I'd
think you'll want a more precise description of your target (i.e.,
just what sort of for loops are useful to the compiler). And then I
think you'll find that not every while loop can be converted into that
form.


Preston Briggs
--

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