[Bug target/91886] [10 regression] powerpc64 impossible constraint in asm

[nsz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91886

--- Comment #6 from nsz at gcc dot gnu.org ---
(In reply to Segher Boessenkool from comment #5)
> -- LLVM should support "wa", since that is *the* constraint for VSX
> registers.
> -- musl should use the "wa" constraint in its inline asm.
> -- If after those two you still want "ws" (for compiling legacy code, say), I
>    can add that back to GCC 10 (it will do just the same as "wa").
> 
> Is that a plan?

llvm only accepts vector types for wa, not scalar types, so there is
a difference between wa and ws in llvm.

i guess musl can switch to wa and configure check if it works (and
disable the asm on compilers where it does not)

but i would prefer if ws and ww were kept as alias to wa in gcc to
avoid breaking existing code (this should not have huge maintenance
cost).