Disappeared flag: -maes on -march=ivybridge, present in -march=native

[Marc Glisse]

On Mon, 29 Jul 2019, Kevin Weidemann wrote:

> I have recently randomly discovered the fact, that building with 
> `-march=ivybridge` does not necessarily produce the same output as 
> `-march=native` on an Intel Core i7 3770K (Ivy Bridge).

Nothing so surprising there. Not all Ivy Bridge processors are equivalent, 
and -march=ivybridge has to conservatively target those with less 
features.

> 71c8e4e2f720bc7155ba2da7c0ee9136a9ab3283 is the first bad commit
> commit 71c8e4e2f720bc7155ba2da7c0ee9136a9ab3283
> Author: hjl <hjl@138bc75d-0d04-0410-961f-82ee72b054a4>
> Date:Â Â  Fri Feb 22 12:49:21 2019 +0000
>
> Â Â Â  x86: (Reapply) Move AESNI generation to Skylake and Goldmont
>
> Â Â Â  This is a repeat of commit r263989, which commit r264052 accidentally
> Â Â Â  reverted.
>
>     2019-02-22  Thiago Macieira  <thiago.macieira@intel.com>
>
> Â Â Â Â Â Â Â Â Â Â Â  PR target/89444
> Â Â Â Â Â Â Â Â Â Â Â  * config/i386/i386.h (PTA_WESTMERE): Remove PTA_AES.
> Â Â Â Â Â Â Â Â Â Â Â  (PTA_SKYLAKE): Add PTA_AES.
> Â Â Â Â Â Â Â Â Â Â Â  (PTA_GOLDMONT): Likewise.

As you can see, this is very much on purpose. See 
https://gcc.gnu.org/ml/gcc-patches/2018-08/msg01940.html for the 
explanation that came with the patch.

-- 
Marc Glisse