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re PR tree-optimization/68892 (Excessive dead loads produced by BB vectorization)

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2015-12-16  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/68892
	* tree-vect-slp.c (vect_analyze_slp_cost_1): Properly compute
	cost for permuted loads.

	* gcc.dg/vect/bb-slp-pr68892.c: New testcase.

From-SVN: r231674
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Richard Biener 2015-12-16 09:21:04 +00:00 • committed by Richard Biener
parent 8ec0963c81
commit 8155f4d8cf
4 changed files with 48 additions and 27 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2015-12-16 Richard Biener <rguenther@suse.de>
PR tree-optimization/68892
* tree-vect-slp.c (vect_analyze_slp_cost_1): Properly compute
cost for permuted loads.
2015-12-16 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/65980

5
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,8 @@
2015-12-16 Richard Biener <rguenther@suse.de>
PR tree-optimization/68892
* gcc.dg/vect/bb-slp-pr68892.c: New testcase.
2015-12-16 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/65980

16
gcc/testsuite/gcc.dg/vect/bb-slp-pr68892.c Normal file
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@ -0,0 +1,16 @@
/* { dg-do compile } */
/* { dg-additional-options "-fvect-cost-model=dynamic" } */
double a[128][128];
double b[128];
void foo(void)
{
b[0] = a[0][0];
b[1] = a[1][0];
b[2] = a[2][0];
b[3] = a[3][0];
}
/* { dg-final { scan-tree-dump "not profitable" "slp2" } } */
/* { dg-final { scan-tree-dump-times "Basic block will be vectorized" 0 "slp2" } } */

48
gcc/tree-vect-slp.c
View file

@ -1402,10 +1402,9 @@ vect_analyze_slp_cost_1 (slp_instance instance, slp_tree node,
{
unsigned i, j;
slp_tree child;
gimple *stmt, *s;
gimple *stmt;
stmt_vec_info stmt_info;
tree lhs;
unsigned group_size = SLP_INSTANCE_GROUP_SIZE (instance);
/* Recurse down the SLP tree. */
FOR_EACH_VEC_ELT (SLP_TREE_CHILDREN (node), i, child)
@ -1424,44 +1423,39 @@ vect_analyze_slp_cost_1 (slp_instance instance, slp_tree node,
node, prologue_cost_vec, body_cost_vec);
else
{
int i;
gcc_checking_assert (DR_IS_READ (STMT_VINFO_DATA_REF (stmt_info)));
/* If the load is permuted then the alignment is determined by
the first group element not by the first scalar stmt DR. */
if (SLP_TREE_LOAD_PERMUTATION (node).exists ())
{
/* If the load is permuted then the alignment is determined by
the first group element not by the first scalar stmt DR. */
stmt = GROUP_FIRST_ELEMENT (stmt_info);
stmt_info = vinfo_for_stmt (stmt);
/* Record the cost for the permutation. */
record_stmt_cost (body_cost_vec, ncopies_for_cost, vec_perm,
stmt_info, 0, vect_body);
/* And adjust the number of loads performed. */
unsigned nunits
= TYPE_VECTOR_SUBPARTS (STMT_VINFO_VECTYPE (stmt_info));
ncopies_for_cost
= (GROUP_SIZE (stmt_info) - GROUP_GAP (stmt_info)
+ nunits - 1) / nunits;
ncopies_for_cost *= SLP_INSTANCE_UNROLLING_FACTOR (instance);
}
/* Record the cost for the vector loads. */
vect_model_load_cost (stmt_info, ncopies_for_cost, false,
node, prologue_cost_vec, body_cost_vec);
/* If the load is permuted record the cost for the permutation.
??? Loads from multiple chains are let through here only
for a single special case involving complex numbers where
in the end no permutation is necessary. */
FOR_EACH_VEC_ELT (SLP_TREE_SCALAR_STMTS (node), i, s)
if ((STMT_VINFO_GROUP_FIRST_ELEMENT (vinfo_for_stmt (s))
== STMT_VINFO_GROUP_FIRST_ELEMENT (stmt_info))
&& vect_get_place_in_interleaving_chain
(s, STMT_VINFO_GROUP_FIRST_ELEMENT (stmt_info)) != i)
{
record_stmt_cost (body_cost_vec, group_size, vec_perm,
stmt_info, 0, vect_body);
break;
}
}
return;
}
else
record_stmt_cost (body_cost_vec, ncopies_for_cost, vector_stmt,
stmt_info, 0, vect_body);
if (SLP_TREE_TWO_OPERATORS (node))
{
record_stmt_cost (body_cost_vec, ncopies_for_cost, vector_stmt,
stmt_info, 0, vect_body);
if (SLP_TREE_TWO_OPERATORS (node))
{
record_stmt_cost (body_cost_vec, ncopies_for_cost, vector_stmt,
stmt_info, 0, vect_body);
record_stmt_cost (body_cost_vec, ncopies_for_cost, vec_perm,
stmt_info, 0, vect_body);
}
record_stmt_cost (body_cost_vec, ncopies_for_cost, vec_perm,
stmt_info, 0, vect_body);
}
/* Push SLP node def-type to stmts. */