re PR tree-optimization/36504 (ICE when building xorg-server with -O3 -fprefetch-loop-arrays)

	PR tree-optimization/36504
	* tree-ssa-loop-prefetch.c (gather_memory_references_ref): Skip
	references without base address.

	* gcc.dg/pr36504.c: New test.

From-SVN: r137061

gcc/ChangeLog

+2008-06-24  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/36504
+	* tree-ssa-loop-prefetch.c (gather_memory_references_ref): Skip
+	references without base address.
+
 2008-06-23  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR middle-end/PR36584

gcc/testsuite/ChangeLog

+2008-06-24  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/36504
+	* gcc.dg/pr36504.c: New test.
+
 2008-06-23  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR middle-end/PR36584

gcc/testsuite/gcc.dg/pr36504.c

+/* PR tree-optimization/36504 */
+/* { dg-do compile } */
+/* { dg-options "-O3 -fprefetch-loop-arrays" } */
+
+struct A { struct { int a; } b[8]; };
+struct B { int c; int d; };
+struct C { struct B d; };
+
+void bar (struct C *, int);
+
+struct B
+foo (struct C *p, struct A *e, int b)
+{
+  struct B q;
+  bar (p, e->b[b].a);
+  return q;
+}
+
+void
+baz (int b, struct A *e)
+{
+  struct C p;
+  for (; b; ++b)
+    p.d = foo (&p, e, b);
+}

gcc/tree-ssa-loop-prefetch.c

@@ -457,6 +457,9 @@ gather_memory_references_ref (struct loop *loop, struct mem_ref_group **refs,
   HOST_WIDE_INT step, delta;
   struct mem_ref_group *agrp;
 
+  if (get_base_address (ref) == NULL)
+    return false;
+
   if (!analyze_ref (loop, &ref, &base, &step, &delta, stmt))
     return false;