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: Fri Feb 22 12:49:21 2019 +0000 x86: (Reapply) Move AESNI generation to Skylake and Goldmont This is a repeat of commit r263989, which commit r264052 accidentally reverted. 2019-02-22 Thiago Macieira <thiago.macie...@intel.com> PR target/89444 * config/i386/i386.h (PTA_WESTMERE): Remove PTA_AES. (PTA_SKYLAKE): Add PTA_AES. (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
