On Wed, Nov 6, 2019 at 5:06 PM Richard Sandiford
wrote:
>
> The gather and scatter optabs required the vector offset to be
> the integer equivalent of the vector mode being loaded or stored.
> This patch generalises them so that the two vectors can have different
> element sizes, although they still need to have the same number of
> elements.
>
> One consequence of this is that it's possible (if unlikely)
> for two IFN_GATHER_LOADs to have the same arguments but different
> return types. E.g. the same scalar base and vector of 32-bit offsets
> could be used to load 8-bit elements and to load 16-bit elements.
> From just looking at the arguments, we could wrongly deduce that
> they're equivalent.
>
> I know we saw this happen at one point with IFN_WHILE_ULT,
> and we dealt with it there by passing a zero of the return type
> as an extra argument. Doing the same here also makes the load
> and store functions have the same argument assignment.
>
> For now this patch should be a no-op, but later SVE patches take
> advantage of the new flexibility.
>
> Tested on aarch64-linux-gnu and x86_64-linux-gnu. OK to install?
OK.
Thanks,
Richard.
> Richard
>
>
> 2019-11-06 Richard Sandiford
>
> gcc/
> * optabs.def (gather_load_optab, mask_gather_load_optab)
> (scatter_store_optab, mask_scatter_store_optab): Turn into
> conversion optabs, with the offset mode given explicitly.
> * doc/md.texi: Update accordingly.
> * config/aarch64/aarch64-sve-builtins-base.cc
> (svld1_gather_impl::expand): Likewise.
> (svst1_scatter_impl::expand): Likewise.
> * internal-fn.c (gather_load_direct, scatter_store_direct): Likewise.
> (expand_scatter_store_optab_fn): Likewise.
> (direct_gather_load_optab_supported_p): Likewise.
> (direct_scatter_store_optab_supported_p): Likewise.
> (expand_gather_load_optab_fn): Likewise. Expect the mask argument
> to be argument 4.
> (internal_fn_mask_index): Return 4 for IFN_MASK_GATHER_LOAD.
> (internal_gather_scatter_fn_supported_p): Replace the offset sign
> argument with the offset vector type. Require the two vector
> types to have the same number of elements but allow their element
> sizes to be different. Treat the optabs as conversion optabs.
> * internal-fn.h (internal_gather_scatter_fn_supported_p): Update
> prototype accordingly.
> * optabs-query.c (supports_at_least_one_mode_p): Replace with...
> (supports_vec_convert_optab_p): ...this new function.
> (supports_vec_gather_load_p): Update accordingly.
> (supports_vec_scatter_store_p): Likewise.
> * tree-vectorizer.h (vect_gather_scatter_fn_p): Take a vec_info.
> Replace the offset sign and bits parameters with a scalar type tree.
> * tree-vect-data-refs.c (vect_gather_scatter_fn_p): Likewise.
> Pass back the offset vector type instead of the scalar element type.
> Allow the offset to be wider than the memory elements. Search for
> an offset type that the target supports, stopping once we've
> reached the maximum of the element size and pointer size.
> Update call to internal_gather_scatter_fn_supported_p.
> (vect_check_gather_scatter): Update calls accordingly.
> When testing a new scale before knowing the final offset type,
> check whether the scale is supported for any signed or unsigned
> offset type. Check whether the target supports the source and
> target types of a conversion before deciding whether to look
> through the conversion. Record the chosen offset_vectype.
> * tree-vect-patterns.c (vect_get_gather_scatter_offset_type): Delete.
> (vect_recog_gather_scatter_pattern): Get the scalar offset type
> directly from the gs_info's offset_vectype instead. Pass a zero
> of the result type to IFN_GATHER_LOAD and IFN_MASK_GATHER_LOAD.
> * tree-vect-stmts.c (check_load_store_masking): Update call to
> internal_gather_scatter_fn_supported_p, passing the offset vector
> type recorded in the gs_info.
> (vect_truncate_gather_scatter_offset): Update call to
> vect_check_gather_scatter, leaving it to search for a valid
> offset vector type.
> (vect_use_strided_gather_scatters_p): Convert the offset to the
> element type of the gs_info's offset_vectype.
> (vect_get_gather_scatter_ops): Get the offset vector type directly
> from the gs_info.
> (vect_get_strided_load_store_ops): Likewise.
> (vectorizable_load): Pass a zero of the result type to IFN_GATHER_LOAD
> and IFN_MASK_GATHER_LOAD.
> * config/aarch64/aarch64-sve.md (gather_load): Rename to...
> (gather_load): ...this.
> (mask_gather_load): Rename to...
> (mask_gather_load): ...this.
> (scatter_store): Rename
