On Mon, Aug 14, 2023 at 04:49:11PM +0800, Xi Ruoyao wrote: > On Mon, 2023-08-14 at 16:44 +0800, Yujie Yang wrote: > > I assume we all want: > > > > (1) -mlasx -mlsx -> enable LSX and LASX > > (2) -mlasx -mno-lsx -> disable LSX and LASX > > (3) -mno-lsx -mlasx -> enable LSX and LASX > > Yes. > > > Unless we declare -mlsx / -mlasx as driver deferred, AFAIK there is no > > other way for > > us to know the actual order of appearnce of all -m[no-]l[a]sx options on > > the command > > line. All we know from GCC's option system would be a final on/off state > > of "lsx" > > and a final on/off state of "lasx". > > But x86 does this correct; > > $ echo __AVX__ + __AVX2__ | LANG= cpp -E -mno-avx -mavx2 > # 0 "<stdin>" > # 0 "<built-in>" > # 0 "<command-line>" > # 1 "/usr/include/stdc-predef.h" 1 3 4 > # 0 "<command-line>" 2 > # 1 "<stdin>" > 1 + 1 > > so there must be a way to handle this... > > -- > Xi Ruoyao <xry...@xry111.site> > School of Aerospace Science and Technology, Xidian University
Emm... What happens if you reverse the order? $ echo __AVX__ + __AVX2__ | LANG= cpp -E -mavx2 -mno-avx Anyways, I believe there may be other ways to implement this, but it would require equally much effort (or even much more) that the current approach. Especially considering the possiblity of future updates -- we now have a framework for this sort of things. Meanwhile you confortably can stay away from -msimd= and use only -mlsx / -mlasx. So...a matter of style maybe?
