re PR lto/46648 (type mismatch in array reference; verify_stmts failed)

2010-11-26  Richard Guenther  <rguenther@suse.de>

	PR lto/46648
	* gimple.c (gtc_visit): Do not return true for members of an
	SCC still being processed but the current lattice value of
	the member.  Treat SCC members comparison state as lattice,
	starting at equal, eventually dropping to unequal.
	(gimple_types_compatible_p_1): Likewise.

	* gcc.dg/lto/20101125-1_0.c: New testcase.
	* gcc.dg/lto/20101125-1_1.c: Likewise.

From-SVN: r167183

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2687d4e6de15b9fbd4f770d2cc176d1aecefeb39..810590c5e139d087296b024b46b98426186c4208 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2010-11-26  Richard Guenther  <rguenther@suse.de>
+
+       PR lto/46648
+       * gimple.c (gtc_visit): Do not return true for members of an
+       SCC still being processed but the current lattice value of
+       the member.  Treat SCC members comparison state as lattice,
+       starting at equal, eventually dropping to unequal.
+       (gimple_types_compatible_p_1): Likewise.
+
 2010-11-26  Richard Guenther  <rguenther@suse.de>
 
        PR middle-end/46559

diff --git a/gcc/gimple.c b/gcc/gimple.c
index 851e30ffbda07e4e0ee3c975c66830b98ee02bf7..67c80e327c3fb99cf4f183ee97b1620e2b7cabeb 100644 (file)
--- a/gcc/gimple.c
+++ b/gcc/gimple.c
@@ -3515,27 +3515,23 @@ gtc_visit (tree t1, tree t2, enum gtc_mode mode,
 
   if ((slot = pointer_map_contains (sccstate, p)) != NULL)
     cstate = (struct sccs *)*slot;
+  /* Not yet visited.  DFS recurse.  */
   if (!cstate)
     {
-      bool res;
-      /* Not yet visited.  DFS recurse.  */
-      res = gimple_types_compatible_p_1 (t1, t2, mode, p,
-                                        sccstack, sccstate, sccstate_obstack);
-      if (!cstate)
-       cstate = (struct sccs *)* pointer_map_contains (sccstate, p);
+      gimple_types_compatible_p_1 (t1, t2, mode, p,
+                                  sccstack, sccstate, sccstate_obstack);
+      cstate = (struct sccs *)* pointer_map_contains (sccstate, p);
       state->low = MIN (state->low, cstate->low);
-      /* If the type is no longer on the SCC stack and thus is not part
-        of the parents SCC, return its state.  Otherwise we will
-        ignore this pair and assume equality.  */
-      if (!cstate->on_sccstack)
-       return res;
     }
+  /* If the type is still on the SCC stack adjust the parents low.  */
   if (cstate->dfsnum < state->dfsnum
       && cstate->on_sccstack)
     state->low = MIN (cstate->dfsnum, state->low);
 
-  /* We are part of our parents SCC, skip this entry and return true.  */
-  return true;
+  /* Return the current lattice value.  We start with an equality
+     assumption so types part of a SCC will be optimistically
+     treated equal unless proven otherwise.  */
+  return cstate->u.same_p;
 }
 
 /* Worker for gimple_types_compatible.
@@ -3559,6 +3555,9 @@ gimple_types_compatible_p_1 (tree t1, tree t2, enum gtc_mode mode,
   state->dfsnum = gtc_next_dfs_num++;
   state->low = state->dfsnum;
   state->on_sccstack = true;
+  /* Start with an equality assumption.  As we DFS recurse into child
+     SCCs this assumption may get revisited.  */
+  state->u.same_p = 1;
 
   /* If their attributes are not the same they can't be the same type.  */
   if (!attribute_list_equal (TYPE_ATTRIBUTES (t1), TYPE_ATTRIBUTES (t2)))
@@ -3822,22 +3821,22 @@ different_types:
 
   /* Common exit path for types that are compatible.  */
 same_types:
-  state->u.same_p = 1;
-  goto pop;
+  gcc_assert (state->u.same_p == 1);
 
 pop:
   if (state->low == state->dfsnum)
     {
       type_pair_t x;
 
-      /* Pop off the SCC and set its cache values.  */
+      /* Pop off the SCC and set its cache values to the final
+         comparison result.  */
       do
        {
          struct sccs *cstate;
          x = VEC_pop (type_pair_t, *sccstack);
          cstate = (struct sccs *)*pointer_map_contains (sccstate, x);
          cstate->on_sccstack = false;
-         x->same_p[mode] = cstate->u.same_p;
+         x->same_p[mode] = state->u.same_p;
        }
       while (x != p);
     }

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 57a7b42cb3913847ebb13d132f6dcc1388967f10..80706c08d1dd8629ef7f633750cc686b26887743 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2010-11-26  Richard Guenther  <rguenther@suse.de>
+
+       PR lto/46648
+       * gcc.dg/lto/20101125-1_0.c: New testcase.
+       * gcc.dg/lto/20101125-1_1.c: Likewise.
+
 2010-11-22   Bud Davis  <jmdavis@link.com>
 
        * arith_divide_no_check.f

diff --git a/gcc/testsuite/gcc.dg/lto/20101125-1_0.c b/gcc/testsuite/gcc.dg/lto/20101125-1_0.c
new file mode 100644 (file)
index 0000000..662dd24
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/20101125-1_0.c
@@ -0,0 +1,24 @@
+/* { dg-lto-do link } */
+
+struct X {
+  int i;
+};
+
+struct W {
+  struct U *p;
+  struct X *q;
+};
+
+struct U {
+  struct W a[1];
+};
+
+void foo(struct U *ptr)
+{
+  ptr->a[0].p = 0;
+}
+
+int main(void)
+{
+  return 0;
+}

diff --git a/gcc/testsuite/gcc.dg/lto/20101125-1_1.c b/gcc/testsuite/gcc.dg/lto/20101125-1_1.c
new file mode 100644 (file)
index 0000000..2924e3f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/20101125-1_1.c
@@ -0,0 +1,17 @@
+struct X {
+  char i;
+};
+
+struct W {
+  struct U *p;
+  struct X *q;
+};
+
+struct U {
+  struct W a[1];
+};
+
+void bar(struct U *ptr)
+{
+  ptr->a[0].p = 0;
+}