Re: Loop unrolling

On Wed, 23 Apr 2008 08:51:41 -0400, Walter Banks wrote:

We have looked at a lot of customer embedded system code related to loop
unrolling and eventually concluded that best thing that we could do in
our compilers was to compile the code as written.

Application code usually was very clear and almost always right in their
timing choice of straight line vs loop implementation. Rolling up
straight line code and unrolling loops more often than not interfered
with a conscience choice a developer made.

Refreshing viewpoint. Maybe like in Java and C# the user could add
comment tags to provide hints, compiler specific, if the compiler used
didn't recognize the tags, they just get ignored so the code remains
compilable across vendor's compilers, but the ones that do recognize them
enables the compiler to attempt to zing the code.

This lets the user become a more active participant, helping guide the
compiler's decisions rather than a less granular command line option
indicating an optimization preference.

--
// This is my opinion.
.

Relevant Pages

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  • Re: Conficker C and Ron Rivest
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  • Re: duffs device / loop unriolling
    ... > With a modern, optimising compiler, it's bad idea. ... > Compilers can do unrolling for you. ... the loop body that is being unrolled is ... The technique of incrementing i by 8, and using 'i+0', etc, ...
    (comp.lang.c)
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    (alt.lang.asm)
  • Re: OT: C++ overloading operators
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