[pypy-dev] Re: psyco in Python was: Minimal Python project

Boyd Roberts boyd at strakt.com
Fri Jan 17 17:50:48 CET 2003


Edward K. Ream wrote:

>I don't think CPU caches have much bearing on this discussion.  Caches speed
>up frequently used values.  The problems here are not the same.
>
I think what you mean here is frequently used code/data as CPU caches
are address based, not value based; locality of reference.

>2. I have looked again at the code generators of the optimizing C compiler I
>wrote about 10 years ago.  I can find no instance where knowing the value
>of an operand, rather than just its type, would produce better code.
>
Zero.  Many redundant instructions can be eliminated on a wide
variety of architectures due to the way the value zero is handled
by the CPU; results of the previous instruction may set condition
codes, instructions that test for zero, ...

Knowlege of values can better construct jump tables for switches.




More information about the Pypy-dev mailing list