On Wed, Aug 09, 2023 at 08:43:00PM +0000, Joseph Myers wrote:
> At this point it seems appropriate to remind people of another ABI
> consideration for vector extensions. glibc's libmvec defines vector
> versions of various functions, including AVX512 ones (of course those
> function versions only work on hardware with the relevant instructions).
> glibc's headers use both _Pragma ("omp declare simd notinbranch") and
> __attribute__ ((__simd__ ("notinbranch"))) to declare, to the compiler
> including those headers, what function variants are available in glibc.
For omp declare simd or simd attribute that simply implies that the
variants with 512-bit vectors may only be called from -mavx512f or
-mavx10.1-512 (or how the switch will be called code), not from -mavx10.1.
We shouldn't change that ABI because of AVX10.
Jakub
