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Superoptimizer – A Look at the Smallest Program (1987) [pdf]

dl.acm.org

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Re: Superoptimizer – A Look at the Smallest Program (1987) [pdf]

#5

Post by convolvatron »

gregdaniels421 wrote: post #3

Same author did the synthesis kernel with Carl Pu, I think? The Synthesis kernel was genius, but relied on self modifying code, so can't work with modern chips well.

yes. Calton Pu. is that really such a problem? JITs seem to work pretty well, I'm pretty sure synthesis was more about creating custom paths than being strictly self-modifying, but it's been a long time.

update: oh, I just remembered why it _is_ an issue for modern processors, Massalin leaned very heavily on the general purpose double compare-and-swap that was present on some generations of the 68k architecture, and x86-64 only has double contiguous compare and swap

Re: Superoptimizer – A Look at the Smallest Program (1987) [pdf]

#6

Post by smalltorch »

Interesting to compare and contrast the human brain in the frame of reference of this superoptimzer paper.

It constantly trys to do the most things with the least things. Take all the shortcuts to achieve the same outcome, often misconstrued with laziness, quality deficiency, or hard to understand.

For example, something as simple as timing may superoptimize and minimize instruction sets. Using one resource to do all the things needed at once versus calling the resource multiple times at different times shrinks the overall program a lot.

Re: Superoptimizer – A Look at the Smallest Program (1987) [pdf]

#8

Post by gregdaniels421 »

convolvatron wrote: post #5
gregdaniels421 wrote: post #3

Same author did the synthesis kernel with Carl Pu, I think? The Synthesis kernel was genius, but relied on self modifying code, so can't work with modern chips well.

yes. Calton Pu. is that really such a problem? JITs seem to work pretty well, I'm pretty sure synthesis was more about creating custom paths than being strictly self-modifying, but it's been a long time. update: oh, I just remembered why it _is_ an issue for modern processors, Massalin leaned very heavily on the general purpose double compare-and-swap that was present on some generations of the 68k architecture, and…

Yeah for the Quajects to get the JIT-ing to work, which was outrageous cool sounding when I first read about it. It is a same we can't figure out how to have nice things like that go fast(cache flushing).
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