On 10.08.2023 15:12, Phoebe Wang wrote: >> The psABI should have some simple rule covering all of the above I think. > > psABI has a rule for the case doesn't mean the rule is a well defined ABI > in practice. A well defined ABI should guarantee 1) interlinkable across > different compile options within the same compiler; 2) interlinkable across > different compilers. Both aspects are failed in the non 512-bit version. > > 1) is more important than 2) and becomes more critical on AVX10 targets. > Because we expect AVX10-256 is a general setting for binaries that can run > on both AVX10-256 and AVX10-512. It would be common that binaries compiled > with AVX10-256 may link with native built binaries on AVX10-512 targets.
But you're only describing a pre-existing problem here afaict. Code compiled with -mavx51f passing __m512 type data to a function compiled with only, say, -maxv2 won't interoperate properly either. What's worse, imo the psABI doesn't sufficiently define what __m256 etc actually are. After all these aren't types defined by the C standard (as opposed to at least most other types in the respective table there), and you can't really make assumptions like "this is what certain compilers think this is". Jan
