On Thu, Jun 19, 2025 at 01:18:10PM GMT, Jakub Jelinek wrote: > On Thu, Jun 19, 2025 at 07:13:07PM +0800, Yang Yujie wrote: > > On Thu, Jun 19, 2025 at 12:32:57PM GMT, Jakub Jelinek wrote: > > > As mentioned in another mail, please follow what aarch64 is doing here (at > > > least unless you explain how it violates your psABI): > > > if (n <= 8) > > > info->limb_mode = QImode; > > > else if (n <= 16) > > > info->limb_mode = HImode; > > > else if (n <= 32) > > > info->limb_mode = SImode; > > > else if (n <= 64) > > > info->limb_mode = DImode; > > > else if (n <= 128) > > > info->limb_mode = TImode; > > > else > > > info->limb_mode = DImode; > > > > > > if (n > 128) > > > info->abi_limb_mode = TImode; > > > else > > > info->abi_limb_mode = info->limb_mode; > > > > If you have a large bigint like _BitInt(191), which takes up an odd number > > of > > 64-bit chunks, I am not sure if lowering with TImode would leave the top > > (unused) > > limb alone. In LoongArch psABI that limb is considered undefined and > > any operations on it should be optimized away. > > I know about that from earlier discussions, but the above code doesn't > change anything on that. 191 is limb_mode DImode, abi_limb_mode TImode like > before. The only thing that changes is the [65, 128] case, in that case > there is no such thing as partial undefined limb and it is much better to > use normal TImode arithmetics and perhaps libcalls for those cases instead > of lowering it.
Ok. Thanks for the comments. Yujie
