The following fixes a latent bug in vect_prune_runtime_alias_test_list,
not considering negative offset1 - offset2.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk
sofar.
Richard.
2016-02-08 Richard Biener <rguent...@suse.de>
PR tree-optimization/69719
* tree-vect-data-refs.c (vect_prune_runtime_alias_test_list):
Properly use absolute of the difference of the two offsets to
compare or adjust the segment length.
* gcc.dg/torture/pr69719.c: New testcase.
Index: gcc/tree-vect-data-refs.c
===================================================================
*** gcc/tree-vect-data-refs.c (revision 233211)
--- gcc/tree-vect-data-refs.c (working copy)
*************** vect_prune_runtime_alias_test_list (loop
*** 2905,2912 ****
|| !tree_fits_shwi_p (dr_a2->offset))
continue;
! HOST_WIDE_INT diff = (tree_to_shwi (dr_a2->offset)
! - tree_to_shwi (dr_a1->offset));
/* Now we check if the following condition is satisfied:
--- 2905,2913 ----
|| !tree_fits_shwi_p (dr_a2->offset))
continue;
! unsigned HOST_WIDE_INT diff
! = absu_hwi (tree_to_shwi (dr_a2->offset)
! - tree_to_shwi (dr_a1->offset));
/* Now we check if the following condition is satisfied:
*************** vect_prune_runtime_alias_test_list (loop
*** 2925,2937 ****
*/
! HOST_WIDE_INT min_seg_len_b = (tree_fits_shwi_p (dr_b1->seg_len)
! ? tree_to_shwi (dr_b1->seg_len)
! : vect_factor);
if (diff <= min_seg_len_b
! || (tree_fits_shwi_p (dr_a1->seg_len)
! && diff - tree_to_shwi (dr_a1->seg_len) < min_seg_len_b))
{
if (dump_enabled_p ())
{
--- 2926,2939 ----
*/
! unsigned HOST_WIDE_INT min_seg_len_b
! = (tree_fits_uhwi_p (dr_b1->seg_len)
! ? tree_to_uhwi (dr_b1->seg_len)
! : vect_factor);
if (diff <= min_seg_len_b
! || (tree_fits_uhwi_p (dr_a1->seg_len)
! && diff - tree_to_uhwi (dr_a1->seg_len) < min_seg_len_b))
{
if (dump_enabled_p ())
{
Index: gcc/testsuite/gcc.dg/torture/pr69719.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr69719.c (revision 0)
--- gcc/testsuite/gcc.dg/torture/pr69719.c (working copy)
***************
*** 0 ****
--- 1,24 ----
+ /* { dg-do run } */
+
+ int b, c = 1, e, f;
+ int a[6][5] = { {0, 0, 0, 0, 0}, {0, 0, 0, 0, 0}, {0, 1, 0, 0, 0} };
+
+ void __attribute__((noinline))
+ fn1 ()
+ {
+ int d;
+ for (b = 0; b < 5; b++)
+ for (d = 4; d; d--)
+ a[c + 1][b] = a[d + 1][d];
+ }
+
+ int
+ main ()
+ {
+ fn1 ();
+
+ if (a[2][1] != 0)
+ __builtin_abort ();
+
+ return 0;
+ }
