Linux-kernel mailing list archive 2000-04,: Re: Code optimization <LEA Instruction>

# Re: Code optimization <LEA Instruction>

Alan Cox (alan@lxorguk.ukuu.org.uk)
Fri, 28 Jan 2000 14:37:52 +0000 (GMT)

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> The test shows that LEA should not be arbitrarily used for arithmetic on
> an index register. It clearly shows that addition is faster.

Arbitarily no, general case it should be.

> It was written to demonstrate this. It demonstrates this. Alan assumed

You wrote a demo for AGI generation stalls not for lea performance when
compiler scheduled. Most x86 chips have a single AGI generator so you
just stalled your cpu a lot.

Alan

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