re PR tree-optimization/48377 (miscompilation at -O3)

	PR tree-optimization/48377
	* tree-vect-data-refs.c (vector_alignment_reachable_p): Set
	is_packed to true even for types with smaller TYPE_ALIGN than
	TYPE_SIZE.

	* gcc.dg/vect/pr48377.c: New test.

From-SVN: r172172

gcc/ChangeLog

+2011-04-08  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/48377
+	* tree-vect-data-refs.c (vector_alignment_reachable_p): Set
+	is_packed to true even for types with smaller TYPE_ALIGN than
+	TYPE_SIZE.
+
 2011-04-08  Richard Guenther  <rguenther@suse.de>
 
 	PR bootstrap/48513

gcc/testsuite/ChangeLog

+2011-04-08  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/48377
+	* gcc.dg/vect/pr48377.c: New test.
+
 2011-04-07  Jason Merrill  <jason@redhat.com>
 
 	* g++.dg/cpp0x/regress/call1.C: New.

gcc/testsuite/gcc.dg/vect/pr48377.c

+/* PR tree-optimization/48377 */
+/* { dg-do run } */
+
+typedef unsigned int U __attribute__((__aligned__ (1), __may_alias__));
+
+__attribute__((noinline, noclone)) unsigned int
+foo (const char *s, int len)
+{
+  const U *p = (const U *) s;
+  unsigned int f = len / sizeof (unsigned int), hash = len, i;
+
+  for (i = 0; i < f; ++i)
+    hash += *p++;
+  return hash;
+}
+
+char buf[64] __attribute__((aligned (32)));
+
+int
+main (void)
+{
+  return foo (buf + 1, 26) != 26;
+}
+
+/* { dg-final { cleanup-tree-dump "vect" } } */

gcc/tree-vect-data-refs.c

 /* Data References Analysis and Manipulation Utilities for Vectorization.
-   Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
+   Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
    Free Software Foundation, Inc.
    Contributed by Dorit Naishlos <dorit@il.ibm.com>
    and Ira Rosen <irar@il.ibm.com>
@@ -1110,6 +1110,9 @@ vector_alignment_reachable_p (struct data_reference *dr)
       if (ba)
 	is_packed = contains_packed_reference (ba);
 
+      if (compare_tree_int (TYPE_SIZE (type), TYPE_ALIGN (type)) > 0)
+	is_packed = true;
+
       if (vect_print_dump_info (REPORT_DETAILS))
 	fprintf (vect_dump, "Unknown misalignment, is_packed = %d",is_packed);
       if (targetm.vectorize.vector_alignment_reachable (type, is_packed))