[PATCH] Fix PR77605

[PATCH] Fix PR77605

[Richard Biener]

The following patch fixes PR77605.

Bootstrap and regtest running on x86_64-unknown-linux-gnu.

Richard.

2016-09-16  Richard Biener  <rguenther@suse.de>

	PR middle-end/77605
	* tree-data-ref.c (analyze_subscript_affine_affine): Use the
	proper niter to bound the loops.

	* gcc.dg/torture/pr77605.c: New testcase.

Index: gcc/tree-data-ref.c
===================================================================
*** gcc/tree-data-ref.c	(revision 240176)
--- gcc/tree-data-ref.c	(working copy)
*************** analyze_subscript_affine_affine (tree ch
*** 2686,2698 ****
  
  	      if (niter > 0)
  		{
! 		  HOST_WIDE_INT tau2 = MIN (FLOOR_DIV (niter - i0, i1),
! 					    FLOOR_DIV (niter - j0, j1));
  		  HOST_WIDE_INT last_conflict = tau2 - (x1 - i0)/i1;
  
  		  /* If the overlap occurs outside of the bounds of the
  		     loop, there is no dependence.  */
! 		  if (x1 >= niter || y1 >= niter)
  		    {
  		      *overlaps_a = conflict_fn_no_dependence ();
  		      *overlaps_b = conflict_fn_no_dependence ();
--- 2682,2694 ----
  
  	      if (niter > 0)
  		{
! 		  HOST_WIDE_INT tau2 = MIN (FLOOR_DIV (niter_a - i0, i1),
! 					    FLOOR_DIV (niter_b - j0, j1));
  		  HOST_WIDE_INT last_conflict = tau2 - (x1 - i0)/i1;
  
  		  /* If the overlap occurs outside of the bounds of the
  		     loop, there is no dependence.  */
! 		  if (x1 >= niter_a || y1 >= niter_b)
  		    {
  		      *overlaps_a = conflict_fn_no_dependence ();
  		      *overlaps_b = conflict_fn_no_dependence ();
Index: gcc/testsuite/gcc.dg/torture/pr77605.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr77605.c	(revision 0)
--- gcc/testsuite/gcc.dg/torture/pr77605.c	(working copy)
***************
*** 0 ****
--- 1,15 ----
+ /* { dg-do run } */
+ 
+ int a, b, c[2][8];
+ 
+ int main ()
+ {
+   for (a = 0; a < 8; a++)
+     for (b = 0; b < 2; b++)
+       c[b][a] = c[b][b + 6] ^ 1;
+ 
+   if (c[0][7] != 0) 
+     __builtin_abort ();
+ 
+   return 0; 
+ }