[PATCH] Fix PR89505

[Richard Biener]

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk 
sofar.

Richard.

2019-02-26  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/89505
        * tree-ssa-structalias.c (compute_dependence_clique): Make sure
        to handle restrict pointed-to vars with multiple subvars
        correctly.

        * gcc.dg/torture/pr89505.c: New testcase.

Index: gcc/tree-ssa-structalias.c
===================================================================
--- gcc/tree-ssa-structalias.c  (revision 269205)
+++ gcc/tree-ssa-structalias.c  (working copy)
@@ -7613,7 +7613,10 @@ compute_dependence_clique (void)
                                              maybe_set_dependence_info);
          if (used)
            {
-             bitmap_set_bit (rvars, restrict_var->id);
+             /* Add all subvars to the set of restrict pointed-to set. */
+             for (unsigned sv = restrict_var->head; sv != 0;
+                  sv = get_varinfo (sv)->next)
+               bitmap_set_bit (rvars, sv);
              varinfo_t escaped = get_varinfo (find (escaped_id));
              if (bitmap_bit_p (escaped->solution, restrict_var->id))
                escaped_p = true;
Index: gcc/testsuite/gcc.dg/torture/pr89505.c
===================================================================
--- gcc/testsuite/gcc.dg/torture/pr89505.c      (nonexistent)
+++ gcc/testsuite/gcc.dg/torture/pr89505.c      (working copy)
@@ -0,0 +1,22 @@
+/* { dg-do run } */
+
+struct S { int i; void *p; int j; };
+int a;
+int __attribute__((noinline))
+foo (struct S * __restrict p, int q)
+{
+  int *x = &p->j;
+  if (q)
+    x = &a;
+  p->j = 1;
+  *x = 2;
+  return p->j;
+}
+
+int main()
+{
+  struct S s;
+  if (foo (&s, 0) != 2)
+    __builtin_abort ();
+  return 0;
+}