poly_int: vectorizable_reduction

This patch makes vectorizable_reduction cope with variable-length vectors.
We can handle the simple case of an inner loop reduction for which
the target has native support for the epilogue operation.  For now we
punt on other cases, but patches after the main SVE submission allow
SLP and double reductions too.

2018-01-03  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* tree.h (build_index_vector): Declare.
	* tree.c (build_index_vector): New function.
	* tree-vect-loop.c (get_initial_defs_for_reduction): Treat the number
	of units as polynomial, forcibly converting it to a constant if
	vectorizable_reduction has already enforced the condition.
	(vect_create_epilog_for_reduction): Likewise.  Use build_index_vector
	to create a {1,2,3,...} vector.
	(vectorizable_reduction): Treat the number of units as polynomial.
	Choose vectype_in based on the largest scalar element size rather
	than the smallest number of units.  Enforce the restrictions
	relied on above.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>

From-SVN: r256133
This commit is contained in:
Richard Sandiford 2018-01-03 07:15:47 +00:00 committed by Richard Sandiford
parent 9031b367ac
commit e54dd6d3a7
4 changed files with 91 additions and 15 deletions

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@ -1,3 +1,19 @@
2018-01-03 Richard Sandiford <richard.sandiford@linaro.org>
Alan Hayward <alan.hayward@arm.com>
David Sherwood <david.sherwood@arm.com>
* tree.h (build_index_vector): Declare.
* tree.c (build_index_vector): New function.
* tree-vect-loop.c (get_initial_defs_for_reduction): Treat the number
of units as polynomial, forcibly converting it to a constant if
vectorizable_reduction has already enforced the condition.
(vect_create_epilog_for_reduction): Likewise. Use build_index_vector
to create a {1,2,3,...} vector.
(vectorizable_reduction): Treat the number of units as polynomial.
Choose vectype_in based on the largest scalar element size rather
than the smallest number of units. Enforce the restrictions
relied on above.
2018-01-03 Richard Sandiford <richard.sandiford@linaro.org>
Alan Hayward <alan.hayward@arm.com>
David Sherwood <david.sherwood@arm.com>

View File

@ -4150,6 +4150,8 @@ get_initial_defs_for_reduction (slp_tree slp_node,
vector_type = STMT_VINFO_VECTYPE (stmt_vinfo);
scalar_type = TREE_TYPE (vector_type);
/* vectorizable_reduction has already rejected SLP reductions on
variable-length vectors. */
nunits = TYPE_VECTOR_SUBPARTS (vector_type);
gcc_assert (STMT_VINFO_DEF_TYPE (stmt_vinfo) == vect_reduction_def);
@ -4537,8 +4539,7 @@ vect_create_epilog_for_reduction (vec<tree> vect_defs, gimple *stmt,
if (STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info) == COND_REDUCTION)
{
tree indx_before_incr, indx_after_incr;
int nunits_out = TYPE_VECTOR_SUBPARTS (vectype);
int k;
poly_uint64 nunits_out = TYPE_VECTOR_SUBPARTS (vectype);
gimple *vec_stmt = STMT_VINFO_VEC_STMT (stmt_info);
gcc_assert (gimple_assign_rhs_code (vec_stmt) == VEC_COND_EXPR);
@ -4554,10 +4555,7 @@ vect_create_epilog_for_reduction (vec<tree> vect_defs, gimple *stmt,
vector size (STEP). */
/* Create a {1,2,3,...} vector. */
tree_vector_builder vtemp (cr_index_vector_type, 1, 3);
for (k = 0; k < 3; ++k)
vtemp.quick_push (build_int_cst (cr_index_scalar_type, k + 1));
tree series_vect = vtemp.build ();
tree series_vect = build_index_vector (cr_index_vector_type, 1, 1);
/* Create a vector of the step value. */
tree step = build_int_cst (cr_index_scalar_type, nunits_out);
@ -4935,8 +4933,11 @@ vect_create_epilog_for_reduction (vec<tree> vect_defs, gimple *stmt,
tree data_eltype = TREE_TYPE (TREE_TYPE (new_phi_result));
tree idx_eltype = TREE_TYPE (TREE_TYPE (induction_index));
unsigned HOST_WIDE_INT el_size = tree_to_uhwi (TYPE_SIZE (idx_eltype));
unsigned HOST_WIDE_INT v_size
= el_size * TYPE_VECTOR_SUBPARTS (TREE_TYPE (induction_index));
poly_uint64 nunits = TYPE_VECTOR_SUBPARTS (TREE_TYPE (induction_index));
/* Enforced by vectorizable_reduction, which ensures we have target
support before allowing a conditional reduction on variable-length
vectors. */
unsigned HOST_WIDE_INT v_size = el_size * nunits.to_constant ();
tree idx_val = NULL_TREE, val = NULL_TREE;
for (unsigned HOST_WIDE_INT off = 0; off < v_size; off += el_size)
{
@ -5055,6 +5056,9 @@ vect_create_epilog_for_reduction (vec<tree> vect_defs, gimple *stmt,
{
bool reduce_with_shift = have_whole_vector_shift (mode);
int element_bitsize = tree_to_uhwi (bitsize);
/* Enforced by vectorizable_reduction, which disallows SLP reductions
for variable-length vectors and also requires direct target support
for loop reductions. */
int vec_size_in_bits = tree_to_uhwi (TYPE_SIZE (vectype));
tree vec_temp;
@ -5743,10 +5747,10 @@ vectorizable_reduction (gimple *stmt, gimple_stmt_iterator *gsi,
if (k == 1
&& gimple_assign_rhs_code (reduc_stmt) == COND_EXPR)
continue;
tem = get_vectype_for_scalar_type (TREE_TYPE (op));
if (! vectype_in
|| TYPE_VECTOR_SUBPARTS (tem) < TYPE_VECTOR_SUBPARTS (vectype_in))
vectype_in = tem;
if (!vectype_in
|| (GET_MODE_SIZE (SCALAR_TYPE_MODE (TREE_TYPE (vectype_in)))
< GET_MODE_SIZE (SCALAR_TYPE_MODE (TREE_TYPE (op)))))
vectype_in = get_vectype_for_scalar_type (TREE_TYPE (op));
break;
}
gcc_assert (vectype_in);
@ -5912,7 +5916,8 @@ vectorizable_reduction (gimple *stmt, gimple_stmt_iterator *gsi,
/* To properly compute ncopies we are interested in the widest
input type in case we're looking at a widening accumulation. */
if (!vectype_in
|| TYPE_VECTOR_SUBPARTS (vectype_in) > TYPE_VECTOR_SUBPARTS (tem))
|| (GET_MODE_SIZE (SCALAR_TYPE_MODE (TREE_TYPE (vectype_in)))
< GET_MODE_SIZE (SCALAR_TYPE_MODE (TREE_TYPE (tem)))))
vectype_in = tem;
}
@ -6097,6 +6102,7 @@ vectorizable_reduction (gimple *stmt, gimple_stmt_iterator *gsi,
gcc_assert (ncopies >= 1);
vec_mode = TYPE_MODE (vectype_in);
poly_uint64 nunits_out = TYPE_VECTOR_SUBPARTS (vectype_out);
if (code == COND_EXPR)
{
@ -6278,14 +6284,23 @@ vectorizable_reduction (gimple *stmt, gimple_stmt_iterator *gsi,
int scalar_precision
= GET_MODE_PRECISION (SCALAR_TYPE_MODE (scalar_type));
cr_index_scalar_type = make_unsigned_type (scalar_precision);
cr_index_vector_type = build_vector_type
(cr_index_scalar_type, TYPE_VECTOR_SUBPARTS (vectype_out));
cr_index_vector_type = build_vector_type (cr_index_scalar_type,
nunits_out);
if (direct_internal_fn_supported_p (IFN_REDUC_MAX, cr_index_vector_type,
OPTIMIZE_FOR_SPEED))
reduc_fn = IFN_REDUC_MAX;
}
if (reduc_fn == IFN_LAST && !nunits_out.is_constant ())
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
"missing target support for reduction on"
" variable-length vectors.\n");
return false;
}
if ((double_reduc
|| STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info) != TREE_CODE_REDUCTION)
&& ncopies > 1)
@ -6297,6 +6312,27 @@ vectorizable_reduction (gimple *stmt, gimple_stmt_iterator *gsi,
return false;
}
if (double_reduc && !nunits_out.is_constant ())
{
/* The current double-reduction code creates the initial value
element-by-element. */
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
"double reduction not supported for variable-length"
" vectors.\n");
return false;
}
if (slp_node && !nunits_out.is_constant ())
{
/* The current SLP code creates the initial value element-by-element. */
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
"SLP reduction not supported for variable-length"
" vectors.\n");
return false;
}
/* In case of widenning multiplication by a constant, we update the type
of the constant to be the type of the other operand. We check that the
constant fits the type in the pattern recognition pass. */

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@ -1930,6 +1930,29 @@ build_vec_series (tree type, tree base, tree step)
return build2 (VEC_SERIES_EXPR, type, base, step);
}
/* Return a vector with the same number of units and number of bits
as VEC_TYPE, but in which the elements are a linear series of unsigned
integers { BASE, BASE + STEP, BASE + STEP * 2, ... }. */
tree
build_index_vector (tree vec_type, poly_uint64 base, poly_uint64 step)
{
tree index_vec_type = vec_type;
tree index_elt_type = TREE_TYPE (vec_type);
poly_uint64 nunits = TYPE_VECTOR_SUBPARTS (vec_type);
if (!INTEGRAL_TYPE_P (index_elt_type) || !TYPE_UNSIGNED (index_elt_type))
{
index_elt_type = build_nonstandard_integer_type
(GET_MODE_BITSIZE (SCALAR_TYPE_MODE (index_elt_type)), true);
index_vec_type = build_vector_type (index_elt_type, nunits);
}
tree_vector_builder v (index_vec_type, 1, 3);
for (unsigned int i = 0; i < 3; ++i)
v.quick_push (build_int_cstu (index_elt_type, base + i * step));
return v.build ();
}
/* Something has messed with the elements of CONSTRUCTOR C after it was built;
calculate TREE_CONSTANT and TREE_SIDE_EFFECTS. */

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@ -4062,6 +4062,7 @@ extern tree make_vector (unsigned, unsigned CXX_MEM_STAT_INFO);
extern tree build_vector_from_ctor (tree, vec<constructor_elt, va_gc> *);
extern tree build_vector_from_val (tree, tree);
extern tree build_vec_series (tree, tree, tree);
extern tree build_index_vector (tree, poly_uint64, poly_uint64);
extern void recompute_constructor_flags (tree);
extern void verify_constructor_flags (tree);
extern tree build_constructor (tree, vec<constructor_elt, va_gc> *);