On Wed, 19 Feb 2020, GT wrote:
> 1. In the Vector Function ABI document, under section "Vector Function
> Name Mangling", state that all <isa> vector variants will be created by
> the compiler. And that it will be up to the caller of vectorized
> functions to select the preferred version ('b' or 'c' are the only
> choices presently).
A reminder, "all" needs to be a particular fixed set that will not be
expanded in future versions of the ABI, so that a glibc installed now
continues to work with future compilers (rather than a future compiler
wrongly taking a pragma / attribute in existing glibc headers as meaning
some future vector ISA variant, unknown when that glibc header was
written, is available). Any future vector ISA variants will need some new
pragma or attribute, naming the variant explicitly, to declare to the
compiler that the library also provides the function for the future ISA
variant. (See <https://gcc.gnu.org/ml/gcc-patches/2019-11/msg01288.html>
for a proposal for extending the simd attribute to allow explicitly
declaring a particular variant to be available.)
--
Joseph S. Myers
[email protected]
