This fixes PR48172 by properly doing the runtime alias check for
vectorization.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk
sofar.
Richard.
2011-05-12 Richard Guenther <rguent...@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.
Index: gcc/tree-vect-loop-manip.c
===================================================================
*** gcc/tree-vect-loop-manip.c (revision 173693)
--- gcc/tree-vect-loop-manip.c (working copy)
*************** vect_create_cond_for_align_checks (loop_
*** 2354,2379 ****
Input:
DR: The data reference.
VECT_FACTOR: vectorization factor.
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)
{
! tree segment_length = fold_build2 (MULT_EXPR, integer_type_node,
! DR_STEP (dr), vect_factor);
!
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);
}
! return fold_convert (sizetype, segment_length);
}
--- 2354,2384 ----
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, int vect_factor,
! tree scalar_loop_niters)
{
! 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 = size_binop (PLUS_EXPR, segment_length, vector_size);
}
! return segment_length;
}
*************** vect_create_cond_for_alias_checks (loop_
*** 2407,2414 ****
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));
ddr_p ddr;
unsigned int i;
--- 2412,2419 ----
struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
VEC (ddr_p, heap) * may_alias_ddrs =
LOOP_VINFO_MAY_ALIAS_DDRS (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;
*************** vect_create_cond_for_alias_checks (loop_
*** 2460,2467 ****
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);
if (vect_print_dump_info (REPORT_DR_DETAILS))
{
--- 2465,2474 ----
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,
! 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))
{
Index: gcc/testsuite/gcc.dg/vect/pr48172.c
===================================================================
*** gcc/testsuite/gcc.dg/vect/pr48172.c (revision 0)
--- gcc/testsuite/gcc.dg/vect/pr48172.c (revision 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" } } */
