J. Gareth Moreton via fpc-devel <fpc-devel@lists.freepascal.org> schrieb am Mi., 1. März 2023, 12:25:
> My peephole optimisations mostly save only a handful of cycles each time > which probably won't add up to much for a relatively short test. The > most major optimisation I can think of, although I'm not quite sure when > it was merged, is the method of replacing divisions by a constant with > an equivalent reciprocal multiplication. You'll see the biggest savings > there. There's other difficulties like processors being intelligent > with caching and out of order execution, for example, that are > disguising some inefficiencies. And some seek only to reduce code size > with no loss of speed. > > What are your timings like when compiling with COREAVX or COREAVX2? A > couple of recent peephole optimizations make use of BMI1 and BMI2. > > I can't remember the proverb that Florian used, but it essentially boils > down to very small changes, individually not amounting to much, but > which accumulate into a noticable difference when in large numbers. > It's a German proverb: "Mühsam ernährt sich das Eichhörnchen" Regards, Sven >
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