Re: [PATCH] Switch vec_init and vec_extract optabs to 2 mode optab to allow extraction of vector from vector or initialization of vector from smaller vectors (PR target/80846)

[Uros Bizjak <ubizjak at gmail dot com>]

On Tue, Jul 25, 2017 at 11:14 AM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> The following patch adjusts the vec_init and vec_extract optabs, so that
> they don't have in the expander names just the vector mode, but also another
> mode, for vec_extract the mode of the result and for vec_init the mode of
> the elts of the vector passed as second operand.
>
> Without this patch, the second mode has been implicit, GET_MODE_INNER of
> the vector mode, so one could just extract a single element from a vector
> or construct vector from elements.  While that is most common, we allow
> in GIMPLE e.g. construction of V8DImode from 4 V2DImode elements etc.
> and the vectorizer uses them.  By having the second mode in the name
> it allows the generic code (vectorizer, expansion) to query whether the
> backend supports such vector from vector expansions or inits from vector
> elts and use them if available.
>
> For vec_extract, if we say want to extract high V2SImode from V4SImode
> the fallback is try to expand it as DImode extraction from V2DImode.
> This works well in many cases, but doesn't really work for very large
> vectors, say if we want to extract high V8SImode from V16SImode on x86,
> we'd need OImode extraction from V2OImode, which is something the backend
> doesn't have any support for.
> For vec_init, the fallback is usually to go through memory, which is slow in
> many cases.
>
> This patch only adds new vector from vector extract and init patterns to
> the i386 backend, but I had to change many other targets too, because
> it needs to have the element mode in the vec_extract/vec_init expander
> names.  Seems most of the backends didn't really have a mode attribute
> usable for this or had it only in uppercase, while for the names we need
> lowercase.  Some backends had a convention on how to name lower case
> vs. upper case modes, others didn't have any.  So I'm CCing maintainers
> of affected backends to seek advice on what mode attributes they want to
> use.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, where it improves
> e.g. the code generation for slp-43.c and slp-45.c testcases.
> make cc1 tested in cross-compilers to the remaining targets.
>
> Ok for trunk?
>
> 2017-07-25  Jakub Jelinek  <jakub@redhat.com>
>
>         PR target/80846
>         * optabs.def (vec_extract_optab, vec_init_optab): Change from
>         a direct optab to conversion optab.
>         * optabs.c (expand_vector_broadcast): Use convert_optab_handler
>         with GET_MODE_INNER as last argument instead of optab_handler.
>         * expmed.c (extract_bit_field_1): Likewise.  Use vector from
>         vector extraction if possible and optab is available.
>         * expr.c (store_constructor): Use convert_optab_handler instead
>         of optab_handler.  Use vector initialization from smaller
>         vectors if possible and optab is available.
>         * tree-vect-stmts.c (vectorizable_load): Likewise.
>         * doc/md.texi (vec_extract, vec_init): Document that the optabs
>         now have two modes.
>         * config/i386/i386.c (ix86_expand_vector_init): Handle expansion
>         of vec_init from half-sized vectors with the same element mode.
>         * config/i386/sse.md (ssehalfvecmode): Add V4TI case.
>         (ssehalfvecmodelower, ssescalarmodelower): New mode attributes.
>         (reduc_plus_scal_v8df, reduc_plus_scal_v4df, reduc_plus_scal_v2df,
>         reduc_plus_scal_v16sf, reduc_plus_scal_v8sf, reduc_plus_scal_v4sf,
>         reduc_<code>_scal_<mode>, reduc_umin_scal_v8hi): Add element mode
>         after mode in gen_vec_extract* calls.
>         (vec_extract<mode>): Renamed to ...
>         (vec_extract<mode><ssescalarmodelower>): ... this.
>         (vec_extract<mode><ssehalfvecmodelower>): New expander.
>         (rotl<mode>3, rotr<mode>3, <shift_insn><mode>3, ashrv2di3): Add
>         element mode after mode in gen_vec_init* calls.
>         (VEC_INIT_HALF_MODE): New mode iterator.
>         (vec_init<mode>): Renamed to ...
>         (vec_init<mode><ssescalarmodelower>): ... this.
>         (vec_init<mode><ssehalfvecmodelower>): New expander.
>         * config/i386/mmx.md (vec_extractv2sf): Renamed to ...
>         (vec_extractv2sfsf): ... this.
>         (vec_initv2sf): Renamed to ...
>         (vec_initv2sfsf): ... this.
>         (vec_extractv2si): Renamed to ...
>         (vec_extractv2sisi): ... this.
>         (vec_initv2si): Renamed to ...
>         (vec_initv2sisi): ... this.
>         (vec_extractv4hi): Renamed to ...
>         (vec_extractv4hihi): ... this.
>         (vec_initv4hi): Renamed to ...
>         (vec_initv4hihi): ... this.
>         (vec_extractv8qi): Renamed to ...
>         (vec_extractv8qiqi): ... this.
>         (vec_initv8qi): Renamed to ...
>         (vec_initv8qiqi): ... this.
>         * config/rs6000/vector.md (VEC_base_l): New mode attribute.
>         (vec_init<mode>): Renamed to ...
>         (vec_init<mode><VEC_base_l>): ... this.
>         (vec_extract<mode>): Renamed to ...
>         (vec_extract<mode><VEC_base_l>): ... this.
>         * config/rs6000/paired.md (vec_initv2sf): Renamed to ...
>         (vec_initv2sfsf): ... this.
>         * config/rs6000/altivec.md (splitter, altivec_copysign_v4sf3,
>         vec_unpacku_hi_v16qi, vec_unpacku_hi_v8hi, vec_unpacku_lo_v16qi,
>         vec_unpacku_lo_v8hi, mulv16qi3, altivec_vreve<mode>2): Add
>         element mode after mode in gen_vec_init* calls.
>         * config/aarch64/aarch64-simd.md (vec_init<mode>): Renamed to ...
>         (vec_init<mode><Vel>): ... this.
>         (vec_extract<mode>): Renamed to ...
>         (vec_extract<mode><Vel>): ... this.
>         * config/aarch64/iterators.md (Vel): New mode attribute.
>         * config/s390/s390.c (s390_expand_vec_strlen, s390_expand_vec_movstr):
>         Add element mode after mode in gen_vec_extract* calls.
>         * config/s390/vector.md (non_vec_l): New mode attribute.
>         (vec_extract<mode>): Renamed to ...
>         (vec_extract<mode><non_vec_l>): ... this.
>         (vec_init<mode>): Renamed to ...
>         (vec_init<mode><non_vec_l>): ... this.
>         * config/s390/s390-builtins.def (s390_vlgvb, s390_vlgvh, s390_vlgvf,
>         s390_vlgvf_flt, s390_vlgvg, s390_vlgvg_dbl): Add element mode after
>         vec_extract mode.
>         * config/arm/iterators.md (V_elem_l): New mode attribute.
>         * config/arm/neon.md (vec_extract<mode>): Renamed to ...
>         (vec_extract<mode><V_elem_l>): ... this.
>         (vec_extractv2di): Renamed to ...
>         (vec_extractv2didi): ... this.
>         (vec_init<mode>): Renamed to ...
>         (vec_init<mode><V_elem_l>): ... this.
>         (reduc_plus_scal_<mode>, reduc_plus_scal_v2di, reduc_smin_scal_<mode>,
>         reduc_smax_scal_<mode>, reduc_umin_scal_<mode>,
>         reduc_umax_scal_<mode>, neon_vget_lane<mode>, neon_vget_laneu<mode>):
>         Add element mode after gen_vec_extract* calls.
>         * config/mips/mips-msa.md (vec_init<mode>): Renamed to ...
>         (vec_init<mode><unitmode>): ... this.
>         (vec_extract<mode>): Renamed to ...
>         (vec_extract<mode><unitmode>): ... this.
>         * config/mips/loongson.md (vec_init<mode>): Renamed to ...
>         (vec_init<mode><unitmode>): ... this.
>         * config/mips/mips-ps-3d.md (vec_initv2sf): Renamed to ...
>         (vec_initv2sfsf): ... this.
>         (vec_extractv2sf): Renamed to ...
>         (vec_extractv2sfsf): ... this.
>         (reduc_plus_scal_v2sf, reduc_smin_scal_v2sf, reduc_smax_scal_v2sf):
>         Add element mode after gen_vec_extract* calls.
>         * config/mips/mips.md (unitmode): New mode iterator.
>         * config/spu/spu.c (spu_expand_prologue, spu_allocate_stack,
>         spu_builtin_extract): Add element mode after gen_vec_extract* calls.
>         * config/spu/spu.md (inner_l): New mode attribute.
>         (vec_init<mode>): Renamed to ...
>         (vec_init<mode><inner_l>): ... this.
>         (vec_extract<mode>): Renamed to ...
>         (vec_extract<mode><inner_l>): ... this.
>         * config/sparc/sparc.md (veltmode): New mode iterator.
>         (vec_init<VMALL:mode>): Renamed to ...
>         (vec_init<VMALL:mode><VMALL:veltmode>): ... this.
>         * config/ia64/vect.md (vec_initv2si): Renamed to ...
>         (vec_initv2sisi): ... this.
>         (vec_initv2sf): Renamed to ...
>         (vec_initv2sfsf): ... this.
>         (vec_extractv2sf): Renamed to ...
>         (vec_extractv2sfsf): ... this.
>         * config/powerpcspe/vector.md (VEC_base_l): New mode attribute.
>         (vec_init<mode>): Renamed to ...
>         (vec_init<mode><VEC_base_l>): ... this.
>         (vec_extract<mode>): Renamed to ...
>         (vec_extract<mode><VEC_base_l>): ... this.
>         * config/powerpcspe/paired.md (vec_initv2sf): Renamed to ...
>         (vec_initv2sfsf): ... this.
>         * config/powerpcspe/altivec.md (splitter, altivec_copysign_v4sf3,
>         vec_unpacku_hi_v16qi, vec_unpacku_hi_v8hi, vec_unpacku_lo_v16qi,
>         vec_unpacku_lo_v8hi, mulv16qi3): Add element mode after mode in
>         gen_vec_init* calls.

OK for the x86 part.

Thanks,
Uros.