sbc100 added a comment. In D151820#4385536 <https://reviews.llvm.org/D151820#4385536>, @dschuff wrote:
>> I don't think it will since `__BIGGEST_ALIGNMENT__ >= >> XNN_ALLOCATION_ALIGNMENT` will remain true after this change.. so this >> change should have no effect on that code. > > I meant that when `__BIGGEST_ALIGNMENT__ >= XNN_ALLOCATION_ALIGNMENT` (which > was true before and will remain true), then XNNPack uses `__builtin_alloca()` > as the implementation of `XNN_SIMD_ALLOCA` (which presumably is for > allocating SIMD values). This change will reduce the alignment used by > `__builtin_alloca()` from 16 to 8, such that (I think) it is no longer > suitable for SIMD values. > > Maybe this is a bug in XNNPack (they should maybe be using > XNN_ALLOCATION_ALIGNMENT with a value suitable for SIMD?) but given that > BIGGEST_ALIGNMENT and alloca seem to be intended for any base type (including > SIMD) it wouldn't be surprising if someone else were depending on this too. XNN_ALLOCATION_ALIGNMENT is 8 under webassembly, which apparently the alignment than xnnpack wants for webassemebly. Using alloca for this is find both before and after this change since both 8 and 18 as fit this requirement. > which... maybe this is just re-litigating the previous discussion, I don't > know. I wonder at what point our ABI should be treating SIMD values as > "normal" rather than rare. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D151820/new/ https://reviews.llvm.org/D151820 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
