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re PR tree-optimization/48172 (incorrect vectorization of loop in GCC 4.5.* with -O3) 

2011-05-12  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/48172
	* tree-vect-loop-manip.c (vect_vfa_segment_size): Do not exclude
	the number of iterations from the segment size calculation.
	(vect_create_cond_for_alias_checks): Adjust.

	* gcc.dg/vect/pr48172.c: New testcase.

From-SVN: r173703
This commit is contained in:
Richard Guenther 2011-05-12 12:14:45 +00:00 committed by Richard Biener
parent 2c703f3a6a
commit e2a3a5f1ad
4 changed files with 63 additions and 11 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
2011-05-12 Richard Guenther <rguenther@suse.de>
PR tree-optimization/48172
* tree-vect-loop-manip.c (vect_vfa_segment_size): Do not exclude
the number of iterations from the segment size calculation.
(vect_create_cond_for_alias_checks): Adjust.
2011-05-12 Jakub Jelinek <jakub@redhat.com>
PR debug/48967

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2011-05-12 Richard Guenther <rguenther@suse.de>
PR tree-optimization/48172
* gcc.dg/vect/pr48172.c: New testcase.
2011-05-12 Jakub Jelinek <jakub@redhat.com>
PR debug/48967

33
gcc/testsuite/gcc.dg/vect/pr48172.c Normal file
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@ -0,0 +1,33 @@
/* { dg-do run } */
extern void *memset(void *s, int c, __SIZE_TYPE__ n);
extern void abort (void);
#define ASIZE 1028
#define HALF (ASIZE/2)
int main() {
unsigned int array[ASIZE];
int i;
memset(array, 0, sizeof(array));
/* initialize first half of the array */
for (i = 0; i < HALF; i++)
array[i] = i;
/* fill second half of array in by summing earlier elements of the array
gcc 4.5.1 and 4.5.2 incorrectly vectorize this loop! aray[1025] is left
at 0 for ASIZE=1028 */
for (i = 0; i < HALF-1; i++)
array[HALF+i] = array[2*i] + array[2*i + 1];
/* see if we have any failures */
for (i = 0; i < HALF - 1; i++)
if (array[HALF+i] != array[2*i] + array[2*i + 1])
abort ();
return 0;
}
/* { dg-final { cleanup-tree-dump "vect" } } */

29
gcc/tree-vect-loop-manip.c
View File

@ -2354,26 +2354,31 @@ vect_create_cond_for_align_checks (loop_vec_info loop_vinfo,
Input:
DR: The data reference.
VECT_FACTOR: vectorization factor.
SCALAR_LOOP_NITERS: number of iterations.
Return an expression whose value is the size of segment which will be
accessed by DR. */
static tree
vect_vfa_segment_size (struct data_reference *dr, tree vect_factor)
vect_vfa_segment_size (struct data_reference *dr, int vect_factor,
tree scalar_loop_niters)
{
tree segment_length = fold_build2 (MULT_EXPR, integer_type_node,
DR_STEP (dr), vect_factor);
tree segment_length;
segment_length = size_binop (MULT_EXPR,
fold_convert (sizetype, DR_STEP (dr)),
size_int (vect_factor));
segment_length = size_binop (MULT_EXPR,
segment_length,
fold_convert (sizetype, scalar_loop_niters));
if (vect_supportable_dr_alignment (dr, false)
== dr_explicit_realign_optimized)
{
tree vector_size = TYPE_SIZE_UNIT
(STMT_VINFO_VECTYPE (vinfo_for_stmt (DR_STMT (dr))));
segment_length = fold_build2 (PLUS_EXPR, integer_type_node,
segment_length, vector_size);
segment_length = size_binop (PLUS_EXPR, segment_length, vector_size);
}
return fold_convert (sizetype, segment_length);
return segment_length;
}
@ -2407,8 +2412,8 @@ vect_create_cond_for_alias_checks (loop_vec_info loop_vinfo,
struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
VEC (ddr_p, heap) * may_alias_ddrs =
LOOP_VINFO_MAY_ALIAS_DDRS (loop_vinfo);
tree vect_factor =
build_int_cst (integer_type_node, LOOP_VINFO_VECT_FACTOR (loop_vinfo));
int vect_factor = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
tree scalar_loop_iters = LOOP_VINFO_NITERS (loop_vinfo);
ddr_p ddr;
unsigned int i;
@ -2460,8 +2465,10 @@ vect_create_cond_for_alias_checks (loop_vec_info loop_vinfo,
vect_create_addr_base_for_vector_ref (stmt_b, cond_expr_stmt_list,
NULL_TREE, loop);
segment_length_a = vect_vfa_segment_size (dr_a, vect_factor);
segment_length_b = vect_vfa_segment_size (dr_b, vect_factor);
segment_length_a = vect_vfa_segment_size (dr_a, vect_factor,
scalar_loop_iters);
segment_length_b = vect_vfa_segment_size (dr_b, vect_factor,
scalar_loop_iters);
if (vect_print_dump_info (REPORT_DR_DETAILS))
{