-march=<name of native> doesn't seem to set flags -march=native does?

[Christer Solskogen]

On 14.07.2016 02.05, Roger Pack wrote:
> Hello.
> As a note after a discussion [1]
>
> I ran into this oddness:
>
>
> $ gcc-6 -march=native -Q --help=target | grep march
>   -march=                     		ivybridge
> $ gcc-6 -march=native -Q --help=target | grep sse3
>   -msse3                      		[enabled]
>   -mssse3                     		[enabled]
> $ gcc-6 -march=ivybridge -Q --help=target | grep sse3
>   -msse3                      		[disabled]
>   -mssse3                     		[disabled]
>
> It appears that specifying (in this case) "-march=ivybridge" which is
> the native, isn't enough/the same as specifying -march=native?
> In addition, the "cache sizes" don't seem to be called out with
> "-march=ivybridge" as they are with "-march=native"
> Anybody know what I'm missing here?
> Thank you!

Happens here as well:

gcc -march=native -Q --help=target | grep march
   -march=                               sandybridge

  gcc -march=native -Q --help=target | grep sse3
   -msse3                                [enabled]
   -mssse3                               [enabled]

gcc -march=sandybridge -Q --help=target | grep sse3
   -msse3                                [disabled]
   -mssse3                               [disabled]

gcc version 5.3.1 20160413 (Ubuntu 5.3.1-14ubuntu2)

-- 
chs