[PATCH] Fix PR69352

[Richard Biener]

The following should fix PR69352 where hash collisions make
equal_mem_array_ref_p get refs it wasn't supposed to compare
and will not compare correctly (those with variable indices).

Profiledbootstrap and testing running on x86_64-unknown-linux-gnu.

Richard.

2016-01-19  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/69352
        * tree-ssa-scopedtables.c (equal_mem_array_ref_p): Constrain
        max size properly.

        * gcc.dg/torture/pr69352.c: New testcase.

Index: gcc/tree-ssa-scopedtables.c
===================================================================
--- gcc/tree-ssa-scopedtables.c (revision 232519)
+++ gcc/tree-ssa-scopedtables.c (working copy)
@@ -261,10 +261,14 @@ equal_mem_array_ref_p (tree t0, tree t1)
   bool rev0;
   HOST_WIDE_INT off0, sz0, max0;
   tree base0 = get_ref_base_and_extent (t0, &off0, &sz0, &max0, &rev0);
+  if (sz0 != max0)
+    return false;
 
   bool rev1;
   HOST_WIDE_INT off1, sz1, max1;
   tree base1 = get_ref_base_and_extent (t1, &off1, &sz1, &max1, &rev1);
+  if (sz1 != max1)
+    return false;
 
   /* Types were compatible, so these are sanity checks.  */
   gcc_assert (sz0 == sz1);
Index: gcc/testsuite/gcc.dg/torture/pr69352.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr69352.c      (revision 0)
--- gcc/testsuite/gcc.dg/torture/pr69352.c      (working copy)
***************
*** 0 ****
--- 1,40 ----
+ /* { dg-do compile } */
+ 
+ int a[10][14], b, c, d, e, f, g, h, i;
+ void bar (void);
+ int
+ foo (int x)
+ {
+   unsigned j;
+   int k = 0, l;
+   int m;
+   if (h)
+     m = 12;
+   else
+     m = 13;
+   if (a[x][m])
+     l = (long) foo;
+   a[x][i] = l;
+   while (c)
+     {
+       if (b)
+       {
+         if (f)
+           k = 1;
+         bar ();
+       }
+       for (; d;)
+       j++;
+     }
+   while (c)
+     {
+       if (a[x][12])
+       {
+         if (g)
+           k = 1;
+         j++;
+       }
+       c = e;
+     }
+   return k;
+ }