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re PR target/83008 ([performance] Is it better to avoid extra instructions in data passing between loops?)

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2018-01-30  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/83008
	* tree-vect-slp.c (vect_analyze_slp_cost_1): Properly cost
	invariant and constant vector uses in stmts when they need
	more than one stmt.

From-SVN: r257181
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Richard Biener 2018-01-30 11:19:47 +00:00 committed by Richard Biener
parent 924d6d0b69
commit 85bb2f9a30
2 changed files with 54 additions and 9 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
2018-01-30 Richard Biener <rguenther@suse.de>
PR tree-optimization/83008
* tree-vect-slp.c (vect_analyze_slp_cost_1): Properly cost
invariant and constant vector uses in stmts when they need
more than one stmt.
2018-01-30 Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>
PR bootstrap/84017

56
gcc/tree-vect-slp.c
View File

@ -1911,18 +1911,56 @@ vect_analyze_slp_cost_1 (slp_instance instance, slp_tree node,
enum vect_def_type dt;
if (!op || op == lhs)
continue;
if (vect_is_simple_use (op, stmt_info->vinfo, &def_stmt, &dt))
if (vect_is_simple_use (op, stmt_info->vinfo, &def_stmt, &dt)
&& (dt == vect_constant_def || dt == vect_external_def))
{
/* Without looking at the actual initializer a vector of
constants can be implemented as load from the constant pool.
??? We need to pass down stmt_info for a vector type
even if it points to the wrong stmt. */
if (dt == vect_constant_def)
record_stmt_cost (prologue_cost_vec, 1, vector_load,
stmt_info, 0, vect_prologue);
else if (dt == vect_external_def)
record_stmt_cost (prologue_cost_vec, 1, vec_construct,
stmt_info, 0, vect_prologue);
When all elements are the same we can use a splat. */
tree vectype = get_vectype_for_scalar_type (TREE_TYPE (op));
unsigned group_size = SLP_TREE_SCALAR_STMTS (node).length ();
unsigned num_vects_to_check;
unsigned HOST_WIDE_INT const_nunits;
unsigned nelt_limit;
if (TYPE_VECTOR_SUBPARTS (vectype).is_constant (&const_nunits)
&& ! multiple_p (const_nunits, group_size))
{
num_vects_to_check = SLP_TREE_NUMBER_OF_VEC_STMTS (node);
nelt_limit = const_nunits;
}
else
{
/* If either the vector has variable length or the vectors
are composed of repeated whole groups we only need to
cost construction once. All vectors will be the same. */
num_vects_to_check = 1;
nelt_limit = group_size;
}
tree elt = NULL_TREE;
unsigned nelt = 0;
for (unsigned j = 0; j < num_vects_to_check * nelt_limit; ++j)
{
unsigned si = j % group_size;
if (nelt == 0)
elt = gimple_op (SLP_TREE_SCALAR_STMTS (node)[si], i);
/* ??? We're just tracking whether all operands of a single
vector initializer are the same, ideally we'd check if
we emitted the same one already. */
else if (elt != gimple_op (SLP_TREE_SCALAR_STMTS (node)[si], i))
elt = NULL_TREE;
nelt++;
if (nelt == nelt_limit)
{
/* ??? We need to pass down stmt_info for a vector type
even if it points to the wrong stmt. */
record_stmt_cost (prologue_cost_vec, 1,
dt == vect_external_def
? (elt ? scalar_to_vec : vec_construct)
: vector_load,
stmt_info, 0, vect_prologue);
nelt = 0;
}
}
}
}