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Re: FTBFS: fftw3

On Fri, Aug 20, 2004 at 07:06:06PM +0100, Dave Love wrote:
> Paul Brossier <piem@altern.org> writes:
> > well, steve's patch only added `--build $(DEB_HOST_GNU_TYPE)' to the
> > configure flags. maybe this gets somehow wrong on sparc. 
> The gcc flags are inconsistent between sparc and x86 (and former gcc
> maintainers can forget which way round they are...).  -mcpu on sparc
> selects the instruction/register set, not just the tuning as it does
> on x86.

Not quite true, I believe. IIRC, i486 -> pentiumpro incurs some
instructions being used in addition to normal x86 instructions.

> For sparc, -mtune=ultrasparc would be reasonable, on the basis that
> number crunching normally should be tuned for recent machines.  On the
> other hand, if it can be made to go significantly faster on ultras by
> compiling with -mcpu=ultrasparc, it would be worth making multiple
> library versions like openssl does.

Similar to how -mcpu=i686 does not run on i386 machines, so
-mcpu=ultrasparc wont run on pre-ultrasparc machines. It's a given. I
can't see how this is confusing.

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