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SubjectRe: -fno-strength-reduce
On Fri, 22 Jan 1999, Arvind Sankar wrote:
> btw, another question along these lines: how much should the alignment
> specs be? The defaults are bigger than what are currently specified
> (currently they are 32 bit alignment for loops, jumps and functions).
> The default is 64-bit on i486 and up, and if gas >= 2.8 is used (likely)
> then it is either 64-bit or 128-bit if you are less than 64 bits from
> a 128-bit boundary. Wouldn't 64-bit alignment be faster for Ppros?

i'm curious about this as well.

i've set alignment on PPro and K6 machines i use to 64 bytes, since the
cache lines on the K6 are 32 bytes each, and are burst loaded from RAM
two-at-a-time. i assume the PPro caches work the same way, but haven't
checked the spec sheet.

perhaps a more reasonable alignment might be 64 bytes for functions, and 8
or 16 bytes for loops and jumps.

the results have been inconclusive, but certainly not dangerous to
performance or stability.

- Chuck Lever
--
corporate: <chuckl@netscape.com>
personal: <chucklever@netscape.net> or <cel@monkey.org>


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