rjmccall added a comment. In D130964#3695408 <https://reviews.llvm.org/D130964#3695408>, @FreddyYe wrote:
> In D130964#3694540 <https://reviews.llvm.org/D130964#3694540>, @bkramer wrote: > >> In D130964#3694473 <https://reviews.llvm.org/D130964#3694473>, @rjmccall >> wrote: >> >>> How are you actually implementing `__bf16` on these targets? There isn't >>> even hardware support for conversions. >> >> `bf16` -> `float` is really just a bit shift. The other direction gets >> lowered to a libcall, compiler-rt has a conversion function with proper >> rounding. I added some support to make the backend promote all other >> arithmetic to float, but I think that's only enabled on x86 so far. > > About hardware support, x86 actually has supported bf16 since AVX512BF16 > (https://reviews.llvm.org/D60552), which has vector conversion support > between float and bf16. Right, but this patch is adding x86 support whenever SSE2 is available. AVX512BF16 is available on a *very* small slice of processors. In contrast, e.g. F16C is relatively broadly available, although I understand that we formally support `_Float16` all the way back to SSE2 and thus on some processors that lack F16C. But okay, pure intrinsic support is fine if that's what we're doing. I think the patch looks fine. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D130964/new/ https://reviews.llvm.org/D130964 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
