How to define multiple processor families?

[Xi Ruoyao]

On 2018-05-07 18:30 +0800, Feng Longda wrote:
> If we set -march/tune to define processor, we can obtain some extra
> performance improvement.
> 
> I want to run my application on different intel processor family, for
> example: broadwell, skylake, haswell, skylake-avx512.
> 
> What should I set? Does It like the following ?
> 
> -march=broadwell   -mtune=intel -mmmx -msse -msse -msse2 -msse3 -mavx
> -mavx2 -mavx=512f -mavx512pf ...

No.  Then GCC would use AVX-512, and the program can't run on processors
without AVX-512.  (You'll see "Illegal Instruction - Core Dumped").

You should use target_clone attribute.
c.f. https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Common-Function-Attributes.html
-- 
Xi Ruoyao <ryxi@stu.xidian.edu.cn>
School of Aerospace Science and Technology, Xidian University