On Fri, May 26, 2023 at 03:07:59PM +0100, Jonathan Wakely wrote:
> > These points are obvious.
> > NOT obvious is but that -m<feature> -march=<lowerISA> does not clear any
> > <feature> not supported in <lowerISA>, i.e the last one does NOT win here.
>
> The last -march option selects the base set of instructions. The -mISA
> options modify that base.
And for -m32 it is also the last option that wins, but as with many other
cases just last one from certain set of options. In the -m32 case,
last one of -m{32,64,x32,m16} option wins. In the -march= case, the
last -march= option wins. In say the PIC/PIE options case, last one
of -f{,no-}{pic,PIC,pie,PIE} option wins. The -mISA options are processed
left to right after setting base from -march=.
Jakub
