* gcc.dg/tree-ssa/20041122-1.c: New test for missing optimization.

Index: 20041122-1.c
===================================================================
RCS file: 20041122-1.c
diff -N 20041122-1.c
*** /dev/null	1 Jan 1970 00:00:00 -0000
--- 20041122-1.c	21 Feb 2005 14:54:12 -0000
***************
*** 0 ****
--- 1,39 ----
+ /* { dg-do compile } */
+ /* { dg-options "-O1 -fdump-tree-dom3" } */
+ 
+ 
+ typedef unsigned int size_t;
+ extern void *xmalloc (size_t) __attribute__ ((__malloc__));
+ struct edge_def
+ {
+   struct basic_block_def *dest;
+   int flags;
+ };
+ typedef struct edge_def *edge;
+ struct basic_block_def
+ {
+   int flags;
+ };
+ typedef struct basic_block_def *basic_block;
+ extern int n_basic_blocks;
+ extern edge frob ();
+ void
+ find_unreachable_blocks (int frobit)
+ {
+   basic_block *tos, *worklist, bb;
+   tos = worklist = xmalloc (sizeof (basic_block) * n_basic_blocks);
+   edge e = frob();
+   if (!(e->dest->flags & 4))
+     {
+       e->dest->flags |= 4;
+       *tos++ = e->dest;
+     }
+ }
+ 
+ /* If the aliasing code does its job properly, then we should be
+    able to determine that modifying e->dest->flags does not
+    modify e or e->dest.  The net result is that we only need one
+    load of e->dest.  */
+ /* { dg-final { scan-tree-dump-times "->dest" 1 "dom3" { xfail *-*-* } } } */
+ 
+