Finding the machine CPU arch

[Ryan Schmidt]

On Mar 6, 2013, at 11:19, Rainer Müller wrote:

> Couldn't we just select variants like +sse, +sse2, etc. based on the
> current architecture?

If it can be separated out like that, sure. But Vincent said atlas will try a bunch of different ways and then pick the fastest one. Hard to make variants for that.


> The following command can be used to check which features with the
> matching command line flags will be selected by -march=native on the
> current hardware:
>  gcc-mp-4.7 -Q --help=target -march=native

The earliest time you can be guaranteed that gcc-mp-4.7 has been installed is in the pre-configure block; by that time, it's too late to select variants.