Re: [RFC] Try vector<bool> as a new representation for vector masks

[Ilya Enkovich <enkovich dot gnu at gmail dot com>]

2015-09-04 23:42 GMT+03:00 Jeff Law <law@redhat.com>:
> On 09/01/2015 07:08 AM, Ilya Enkovich wrote:
>>
>> On 27 Aug 09:55, Richard Biener wrote:
>>>
>>> I suggest you try modifying those parts first according to this
>>> scheme that will most likely uncover issues we missed.
>>>
>>> Thanks, Richard.
>>>
>>
>> I tried to implement this scheme and apply it for MASK_LOAD and
>> MASK_STORE.  There were no major issues (for now).
>
> So do we have enough confidence in this representation that we want to go
> ahead and commit to it?

I think new representation fits nice mostly. There are some places
where I have to make some exceptions for vector of bools to make it
work. This is mostly to avoid target modifications. I'd like to avoid
necessity to change all targets currently supporting vec_cond. It
makes me add some special handling of vec<bool> in GIMPLE, e.g. I add
a special code in vect_init_vector to build vec<bool> invariants with
proper casting to int. Otherwise I'd need to do it on a target side.

I made several fixes and current patch (still allowing integer vector
result for vector comparison and applying bool patterns) passes
bootstrap and regression testing on x86_64. Now I'll try to fully
switch to vec<bool> and see how it goes.

Thanks,
Ilya

>
>>
>> I had to introduce significant number of new patterns in i386 target
>> to support new optabs.  The reason was vector compare was never
>> expanded separately and always was a part of a vec_cond expansion.
>
> One could argue we should have fixed this already, so I don't see the new
> patterns as a bad thing, but instead they're addressing a long term
> mis-design.
>
>>
>>
>> For now I still don't disable bool patterns, thus new masks apply to
>> masked loads and stores only.  Patch is also not tested and tried on
>> several small tests only.  Could you please look at what I currently
>> have and say if it's in sync with your view on vector masking?
>
> I'm going to let Richi run with this for the most part -- but I will chime
> in with a thank you for being willing to bounce this around a bit while we
> figure out the representational issues.
>
>
> jeff



gcc/

2015-09-08  Ilya Enkovich  <enkovich.gnu@gmail.com>

* config/i386/i386-protos.h (ix86_expand_mask_vec_cmp): New.
(ix86_expand_int_vec_cmp): New.
(ix86_expand_fp_vec_cmp): New.
* config/i386/i386.c (ix86_expand_sse_cmp): Allow NULL for
op_true and op_false.
(ix86_int_cmp_code_to_pcmp_immediate): New.
(ix86_fp_cmp_code_to_pcmp_immediate): New.
(ix86_cmp_code_to_pcmp_immediate): New.
(ix86_expand_mask_vec_cmp): New.
(ix86_expand_fp_vec_cmp): New.
(ix86_expand_int_sse_cmp): New.
(ix86_expand_int_vcond): Use ix86_expand_int_sse_cmp.
(ix86_expand_int_vec_cmp): New.
(ix86_get_mask_mode): New.
(TARGET_VECTORIZE_GET_MASK_MODE): New.
* config/i386/sse.md (avx512fmaskmodelower): New.
(vec_cmp<mode><avx512fmaskmodelower>): New.
(vec_cmp<mode><sseintvecmodelower>): New.
(vec_cmpv2div2di): New.
(vec_cmpu<mode><avx512fmaskmodelower>): New.
(vec_cmpu<mode><sseintvecmodelower>): New.
(vec_cmpuv2div2di): New.
(maskload<mode>): Rename to ...
(maskload<mode><sseintvecmodelower>): ... this.
(maskstore<mode>): Rename to ...
(maskstore<mode><sseintvecmodelower>): ... this.
(maskload<mode><avx512fmaskmodelower>): New.
(maskstore<mode><avx512fmaskmodelower>): New.
* doc/tm.texi: Regenerated.
* doc/tm.texi.in (TARGET_VECTORIZE_GET_MASK_MODE): New.
* expr.c (do_store_flag): Use expand_vec_cmp_expr for mask results.
* internal-fn.c (expand_MASK_LOAD): Adjust to optab changes.
(expand_MASK_STORE): Likewise.
* optabs.c (vector_compare_rtx): Add OPNO arg.
(expand_vec_cond_expr): Adjust to vector_compare_rtx change.
(get_vec_cmp_icode): New.
(expand_vec_cmp_expr_p): New.
(expand_vec_cmp_expr): New.
(can_vec_mask_load_store_p): Add MASK_MODE arg.
* optabs.def (vec_cmp_optab): New.
(vec_cmpu_optab): New.
(maskload_optab): Transform into convert optab.
(maskstore_optab): Likewise.
* optabs.h (expand_vec_cmp_expr_p): New.
(expand_vec_cmp_expr): New.
(can_vec_mask_load_store_p): Add MASK_MODE arg.
* target.def (get_mask_mode): New.
* targhooks.c (default_vector_alignment): Use mode alignment
for vector masks.
(default_get_mask_mode): New.
* targhooks.h (default_get_mask_mode): New.
* tree-cfg.c (verify_gimple_comparison): Support vector mask.
* tree-if-conv.c (ifcvt_can_use_mask_load_store): Adjust to
can_vec_mask_load_store_p signature change.
(predicate_mem_writes): Use boolean mask.
* tree-vect-data-refs.c (vect_get_new_vect_var): Support vect_mask_var.
(vect_create_destination_var): Likewise.
* tree-vect-generic.c (expand_vector_comparison): Use
expand_vec_cmp_expr_p for comparison availability.
(expand_vector_operations_1): Ignore mask statements with scalar mode.
* tree-vect-loop.c (vect_determine_vectorization_factor): Ignore mask
operations for VF.  Add mask type computation.
* tree-vect-stmts.c (vect_init_vector): Support mask invariants.
(vect_get_vec_def_for_operand): Support mask constant.
(vectorizable_mask_load_store): Adjust to can_vec_mask_load_store_p
signature change.
(vectorizable_comparison): New.
(vect_analyze_stmt): Add vectorizable_comparison.
(vect_transform_stmt): Likewise.
(get_mask_type_for_scalar_type): New.
* tree-vectorizer.h (enum stmt_vec_info_type): Add vect_mask_var
(enum stmt_vec_info_type): Add comparison_vec_info_type.
(get_mask_type_for_scalar_type): New.
* tree.c (build_truth_vector_type): New.
(truth_type_for): Use build_truth_vector_type for vectors.
* tree.h (build_truth_vector_type): New.

Attachment: avx512-vec-bool.patch
Description: Binary data