On Wed, Jun 13, 2012 at 4:18 AM, William J. Schmidt
<wschm...@linux.vnet.ibm.com> wrote:
> This patch is a follow-up to the discussion generated by
> http://gcc.gnu.org/ml/gcc-patches/2012-06/msg00546.html. I've added
> vec_construct to the cost model for use in vect_model_load_cost, and
> implemented a cost calculation that makes sense to me for PowerPC. I'm
> less certain about the default, i386, and spu implementations. I took a
> guess at i386 from the discussions we had, and used the same calculation
> for the default and for spu. I'm hoping you or others can fill in the
> blanks if I guessed badly.
>
> The i386 cost for vec_construct is different from all the others, which
> are parameterized for each processor description. This should probably
> be parameterized in some way as well, but thought you'd know better than
> I how that should be. Perhaps instead of
>
> elements / 2 + 1
>
> it should be
>
> (elements / 2) * X + Y
>
> where X and Y are taken from the processor description, and represent
> the cost of a merge and a permute, respectively. Let me know what you
> think.
Just trying to understand how you arrived at the above formulas in investigating
strangely low cost for v16qi construction of 9. If we pairwise reduce elements
with a cost of 1 then we arrive at a cost of elements - 1, that's what you'd
get with not accounting an initial move of element zero into a vector and then
inserting each other element into that with elements - 1 inserts.
This also matches up with code-generation on x86_64 for
vT foo (T a, T b, ...)
{
return (vT) {a, b, ... };
}
for any vector / element type combination I tried. Thus the patch below.
I'll bootstrap / test that on x86_64-linux and I'm leaving other
targets to target
maintainers.
Ok for the i386 parts?
Thanks,
Richard.
2016-06-08 Richard Biener <rguent...@suse.de>
* targhooks.c (default_builtin_vectorization_cost): Adjust
vec_construct cost.
* config/i386/i386.c (ix86_builtin_vectorization_cost): Likewise.
Index: gcc/targhooks.c
===================================================================
--- gcc/targhooks.c (revision 237196)
+++ gcc/targhooks.c (working copy)
@@ -589,8 +589,7 @@ default_builtin_vectorization_cost (enum
return 3;
case vec_construct:
- elements = TYPE_VECTOR_SUBPARTS (vectype);
- return elements / 2 + 1;
+ return TYPE_VECTOR_SUBPARTS (vectype) - 1;
default:
gcc_unreachable ();
Index: gcc/config/i386/i386.c
===================================================================
--- gcc/config/i386/i386.c (revision 237196)
+++ gcc/config/i386/i386.c (working copy)
@@ -49503,8 +49520,6 @@ static int
ix86_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost,
tree vectype, int)
{
- unsigned elements;
-
switch (type_of_cost)
{
case scalar_stmt:
@@ -49546,8 +49561,7 @@ ix86_builtin_vectorization_cost (enum ve
return ix86_cost->vec_stmt_cost;
case vec_construct:
- elements = TYPE_VECTOR_SUBPARTS (vectype);
- return ix86_cost->vec_stmt_cost * (elements / 2 + 1);
+ return ix86_cost->vec_stmt_cost * (TYPE_VECTOR_SUBPARTS (vectype) - 1);
default:
gcc_unreachable ();
> Thanks,
> Bill
>
>
> 2012-06-12 Bill Schmidt <wschm...@linux.ibm.com>
>
> * targhooks.c (default_builtin_vectorized_conversion): Handle
> vec_construct, using vectype to base cost on subparts.
> * target.h (enum vect_cost_for_stmt): Add vec_construct.
> * tree-vect-stmts.c (vect_model_load_cost): Use vec_construct
> instead of scalar_to-vec.
> * config/spu/spu.c (spu_builtin_vectorization_cost): Handle
> vec_construct in same way as default for now.
> * config/i386/i386.c (ix86_builtin_vectorization_cost): Likewise.
> * config/rs6000/rs6000.c (rs6000_builtin_vectorization_cost):
> Handle vec_construct, including special case for 32-bit loads.
>
>
> Index: gcc/targhooks.c
> ===================================================================
> --- gcc/targhooks.c (revision 188482)
> +++ gcc/targhooks.c (working copy)
> @@ -499,9 +499,11 @@ default_builtin_vectorized_conversion (unsigned in
>
> int
> default_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost,
> - tree vectype ATTRIBUTE_UNUSED,
> + tree vectype,
> int misalign ATTRIBUTE_UNUSED)
> {
> + unsigned elements;
> +
> switch (type_of_cost)
> {
> case scalar_stmt:
> @@ -524,6 +526,11 @@ default_builtin_vectorization_cost (enum vect_cost
> case cond_branch_taken:
> return 3;
>
> + case vec_construct:
> + elements = TYPE_VECTOR_SUBPARTS (vectype);
> + gcc_assert (elements > 1);
> + return elements / 2 + 1;
> +
> default:
> gcc_unreachable ();
> }
> Index: gcc/target.h
> ===================================================================
> --- gcc/target.h (revision 188482)
> +++ gcc/target.h (working copy)
> @@ -146,7 +146,8 @@ enum vect_cost_for_stmt
> cond_branch_not_taken,
> cond_branch_taken,
> vec_perm,
> - vec_promote_demote
> + vec_promote_demote,
> + vec_construct
> };
>
> /* The target structure. This holds all the backend hooks. */
> Index: gcc/tree-vect-stmts.c
> ===================================================================
> --- gcc/tree-vect-stmts.c (revision 188482)
> +++ gcc/tree-vect-stmts.c (working copy)
> @@ -1031,11 +1031,13 @@ vect_model_load_cost (stmt_vec_info stmt_info, int
> /* The loads themselves. */
> if (STMT_VINFO_STRIDE_LOAD_P (stmt_info))
> {
> - /* N scalar loads plus gathering them into a vector.
> - ??? scalar_to_vec isn't the cost for that. */
> + /* N scalar loads plus gathering them into a vector. */
> + tree vectype = STMT_VINFO_VECTYPE (stmt_info);
> inside_cost += (vect_get_stmt_cost (scalar_load) * ncopies
> - * TYPE_VECTOR_SUBPARTS (STMT_VINFO_VECTYPE
> (stmt_info)));
> - inside_cost += ncopies * vect_get_stmt_cost (scalar_to_vec);
> + * TYPE_VECTOR_SUBPARTS (vectype));
> + inside_cost += ncopies
> + * targetm.vectorize.builtin_vectorization_cost (vec_construct,
> + vectype, 0);
> }
> else
> vect_get_load_cost (first_dr, ncopies,
> Index: gcc/config/spu/spu.c
> ===================================================================
> --- gcc/config/spu/spu.c (revision 188482)
> +++ gcc/config/spu/spu.c (working copy)
> @@ -6908,9 +6908,11 @@ spu_builtin_mask_for_load (void)
> /* Implement targetm.vectorize.builtin_vectorization_cost. */
> static int
> spu_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost,
> - tree vectype ATTRIBUTE_UNUSED,
> + tree vectype,
> int misalign ATTRIBUTE_UNUSED)
> {
> + unsigned elements;
> +
> switch (type_of_cost)
> {
> case scalar_stmt:
> @@ -6937,6 +6939,11 @@ spu_builtin_vectorization_cost (enum vect_cost_for
> case cond_branch_taken:
> return 6;
>
> + case vec_construct:
> + elements = TYPE_VECTOR_SUBPARTS (vectype);
> + gcc_assert (elements > 1);
> + return elements / 2 + 1;
> +
> default:
> gcc_unreachable ();
> }
> Index: gcc/config/i386/i386.c
> ===================================================================
> --- gcc/config/i386/i386.c (revision 188482)
> +++ gcc/config/i386/i386.c (working copy)
> @@ -36072,9 +36072,11 @@ static const struct attribute_spec ix86_attribute_
> /* Implement targetm.vectorize.builtin_vectorization_cost. */
> static int
> ix86_builtin_vectorization_cost (enum vect_cost_for_stmt type_of_cost,
> - tree vectype ATTRIBUTE_UNUSED,
> + tree vectype,
> int misalign ATTRIBUTE_UNUSED)
> {
> + unsigned elements;
> +
> switch (type_of_cost)
> {
> case scalar_stmt:
> @@ -36115,6 +36117,11 @@ ix86_builtin_vectorization_cost (enum vect_cost_fo
> case vec_promote_demote:
> return ix86_cost->vec_stmt_cost;
>
> + case vec_construct:
> + elements = TYPE_VECTOR_SUBPARTS (vectype);
> + gcc_assert (elements > 1);
> + return elements / 2 + 1;
> +
> default:
> gcc_unreachable ();
> }
> Index: gcc/config/rs6000/rs6000.c
> ===================================================================
> --- gcc/config/rs6000/rs6000.c (revision 188482)
> +++ gcc/config/rs6000/rs6000.c (working copy)
> @@ -3405,6 +3405,7 @@ rs6000_builtin_vectorization_cost (enum vect_cost_
> tree vectype, int misalign)
> {
> unsigned elements;
> + tree elem_type;
>
> switch (type_of_cost)
> {
> @@ -3504,6 +3505,19 @@ rs6000_builtin_vectorization_cost (enum vect_cost_
>
> return 2;
>
> + case vec_construct:
> + elements = TYPE_VECTOR_SUBPARTS (vectype);
> + elem_type = TREE_TYPE (vectype);
> + gcc_assert (elements > 1);
> + /* 32-bit vectors loaded into registers are stored as double
> + precision, so we need n/2 converts in addition to the usual
> + n/2 merges to construct a vector of short floats from them. */
> + if (SCALAR_FLOAT_TYPE_P (elem_type)
> + && TYPE_PRECISION (elem_type) == 32)
> + return elements + 1;
> + else
> + return elements / 2 + 1;
> +
> default:
> gcc_unreachable ();
> }
>
>
