Re: Is global optimization worth it?

        My belief is that global optimization will save you only about 20% in
terms of time. However, it certain cases it could be 200%. For example,
consider the following code fragment:
                for i = 0 to 99
                        a[i] = 0;
Turning the above code fragment into a single block move could be a big win
here. My advice to you is try to avoid writing a global optimizer but leave
room for it in your design so that if you need to you can go back an add it
latter. In general, I would leave the hooks in to for a variety of different
optimizations but do none of them until my compiler was working.


        By the way, I have fond that the iterative methods are significantly
easier to implement then something like T1-T2 analysis.




                                                                                        Robert Sherry




"Lance" <lance.delahaye@xtra.co.nz> wrote in message
> I'm starting a compiler project. I am wondering if it is worth
> ignoring global optimisations for a pascal-type scoped language. About
> how much optimisation gain is there to be had there? If its more than
> about a third, I probably shouldn't ignore it, but it would simplify
> my life quite a bit if I could.

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