On Mon, Aug 14, 2023 at 01:22:32PM +0800, Xi Ruoyao wrote:
> On Mon, 2023-08-14 at 11:57 +0800, Yang Yujie wrote:
> > The configure script and the GCC driver are updated so that
> > it is easier to customize and control GCC builds for targeting
> > different LoongArch implementations.
> >
> > * Support options for LoongArch SIMD extensions:
> > new configure options --with-simd={none,lsx,lasx};
> > new driver options -m[no]-l[a]sx / -msimd={none,lsx,lasx}.
>
> What's the relationship between -mlasx and -msimd=lasx? What will
> happen if the user specifies -mlasx -msimd=none or -mlasx -msimd=lsx?
>
> --
> Xi Ruoyao <xry...@xry111.site>
> School of Aerospace Science and Technology, Xidian University
At this moment we make sure all "flags" (that expresses a config "delta")
are processed after the "parameters", which is documented in the LoongArch
Toolchain Conventions[1].
So if -msimd=* and -m[no-]l[a]sx appear together on the driver command
line, the final configuration would be derived by first applying -msimd=*
and then the sequence of -m[no-]l[a]sx, in the order they appear.
This is similar to the relationship between -msoft-float and -mfpu / -mabi,
where -mfpu / -mabi are applied first, and -msoft-float modifies the existing
target configuration states (FPU, ABI).
[1] currently released at https://github.com/loongson/LoongArch-Documentation
/blob/main/docs/LoongArch-toolchain-conventions-EN.adoc
