Richard Guenther <richard.guent...@gmail.com> writes:
> On Tue, Apr 12, 2011 at 3:59 PM, Richard Sandiford
> <richard.sandif...@linaro.org> wrote:
>> This patch adds vec_load_lanes and vec_store_lanes optabs for instructions
>> like NEON's vldN and vstN. The optabs are defined this way because the
>> vectors must be allocated to a block of consecutive registers.
>>
>> Tested on x86_64-linux-gnu and arm-linux-gnueabi. OK to install?
>>
>> Richard
>>
>>
>> gcc/
>> * doc/md.texi (vec_load_lanes, vec_store_lanes): Document.
>> * optabs.h (COI_vec_load_lanes, COI_vec_store_lanes): New
>> convert_optab_index values.
>> (vec_load_lanes_optab, vec_store_lanes_optab): New convert optabs.
>> * genopinit.c (optabs): Initialize the new optabs.
>> * internal-fn.def (LOAD_LANES, STORE_LANES): New internal functions.
>> * internal-fn.c (get_multi_vector_move, expand_LOAD_LANES)
>> (expand_STORE_LANES): New functions.
>> * tree.h (build_simple_array_type): Declare.
>> * tree.c (build_simple_array_type): New function.
>> * tree-vectorizer.h (vect_model_store_cost): Add a bool argument.
>> (vect_model_load_cost): Likewise.
>> (vect_store_lanes_supported, vect_load_lanes_supported)
>> (vect_record_strided_load_vectors): Declare.
>> * tree-vect-data-refs.c (vect_lanes_optab_supported_p)
>> (vect_store_lanes_supported, vect_load_lanes_supported): New
>> functions.
>> (vect_transform_strided_load): Split out statement recording into...
>> (vect_record_strided_load_vectors): ...this new function.
>> * tree-vect-stmts.c (create_vector_array, read_vector_array)
>> (write_vector_array, create_array_ref): New functions.
>> (vect_model_store_cost): Add store_lanes_p argument.
>> (vect_model_load_cost): Add load_lanes_p argument.
>> (vectorizable_store): Try to use store-lanes functions for
>> interleaved stores.
>> (vectorizable_load): Likewise load-lanes and loads.
>> * tree-vect-slp.c (vect_get_and_check_slp_defs)
>> (vect_build_slp_tree):
>>
>> Index: gcc/doc/md.texi
>> ===================================================================
>> --- gcc/doc/md.texi 2011-04-12 12:16:46.000000000 +0100
>> +++ gcc/doc/md.texi 2011-04-12 14:48:28.000000000 +0100
>> @@ -3846,6 +3846,48 @@ into consecutive memory locations. Oper
>> consecutive memory locations, operand 1 is the first register, and
>> operand 2 is a constant: the number of consecutive registers.
>>
>> +@cindex @code{vec_load_lanes@var{m}@var{n}} instruction pattern
>> +@item @samp{vec_load_lanes@var{m}@var{n}}
>> +Perform an interleaved load of several vectors from memory operand 1
>> +into register operand 0. Both operands have mode @var{m}. The register
>> +operand is viewed as holding consecutive vectors of mode @var{n},
>> +while the memory operand is a flat array that contains the same number
>> +of elements. The operation is equivalent to:
>> +
>> +@smallexample
>> +int c = GET_MODE_SIZE (@var{m}) / GET_MODE_SIZE (@var{n});
>> +for (j = 0; j < GET_MODE_NUNITS (@var{n}); j++)
>> + for (i = 0; i < c; i++)
>> + operand0[i][j] = operand1[j * c + i];
>> +@end smallexample
>> +
>> +For example, @samp{vec_load_lanestiv4hi} loads 8 16-bit values
>> +from memory into a register of mode @samp{TI}@. The register
>> +contains two consecutive vectors of mode @samp{V4HI}@.
>
> So vec_load_lanestiv2qi would load ... ? c == 8 here. Intuitively
> such operation would have adjacent blocks of siv2qi memory. But
> maybe you want to constrain the mode size to GET_MODE_SIZE (@var{n})
> * GET_MODE_NUNITS (@var{n})? In which case the mode m is
> redundant? You could specify that we load NUNITS adjacent vectors into
> an integer mode of appropriate size.
Like you say, vec_load_lanestiv2qi would load 16 QImode elements into
8 consecutive V2QI registers. The first element from register vector I
would come from operand1[I] and the second element would come from
operand1[I + 8]. That's meant to be a valid combination.
We specifically want to allow:
GET_MODE_SIZE (@var{m})
!= GET_MODE_SIZE (@var{n}) * GET_MODE_NUNITS (@var{n})
The vec_load_lanestiv4hi example in the docs is one case of this:
GET_MODE_SIZE (@var{m}) = 16
GET_MODE_SIZE (@var{n}) = 8
GET_MODE_NUNITS (@var{n}) = 4
That example maps directly to ARM's vld2.32. We also want cases
where @var{m} is three times the size of @var{n} (vld3.WW) and
cases where @var{m} is four times the size of @var{n} (vld4.WW)
>> +/* Return a representation of ELT_TYPE[NELTS], using indices of type
>> + sizetype. */
>> +
>> +tree
>> +build_simple_array_type (tree elt_type, unsigned HOST_WIDE_INT nelts)
>
> build_array_type_nelts
OK.
Richard
