Fix alignment of vectorizer generated pointers

Message ID alpine.LNX.2.00.1012071730080.23074@zhemvz.fhfr.qr
State New
Headers show

Commit Message

Richard Biener Dec. 7, 2010, 4:31 p.m.
For those pointers the vectorizer doesn't base accesses off we
have to watch out when copying SSA name pointer information as
offsetting them invalidates alignment information.  This was
noticed by Micha when working on some patch.

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

Richard.

2010-12-07  Richard Guenther  <rguenther@suse.de>

	* tree-vect-data-refs.c (vect_create_addr_base_for_vector_ref):
	Reset alignment information.
	(bump_vector_ptr): Likewise.

Patch

Index: gcc/tree-vect-data-refs.c
===================================================================
--- gcc/tree-vect-data-refs.c	(revision 167534)
+++ gcc/tree-vect-data-refs.c	(working copy)
@@ -2918,7 +2918,14 @@  vect_create_addr_base_for_vector_ref (gi
 
   if (DR_PTR_INFO (dr)
       && TREE_CODE (vec_stmt) == SSA_NAME)
-    duplicate_ssa_name_ptr_info (vec_stmt, DR_PTR_INFO (dr));
+    {
+      duplicate_ssa_name_ptr_info (vec_stmt, DR_PTR_INFO (dr));
+      if (offset)
+	{
+	  SSA_NAME_PTR_INFO (vec_stmt)->align = 1;
+	  SSA_NAME_PTR_INFO (vec_stmt)->misalign = 0;
+	}
+    }
 
   if (vect_print_dump_info (REPORT_DETAILS))
     {
@@ -3308,7 +3315,11 @@  bump_vector_ptr (tree dataref_ptr, gimpl
 
   /* Copy the points-to information if it exists. */
   if (DR_PTR_INFO (dr))
-    duplicate_ssa_name_ptr_info (new_dataref_ptr, DR_PTR_INFO (dr));
+    {
+      duplicate_ssa_name_ptr_info (new_dataref_ptr, DR_PTR_INFO (dr));
+      SSA_NAME_PTR_INFO (new_dataref_ptr)->align = 1;
+      SSA_NAME_PTR_INFO (new_dataref_ptr)->misalign = 0;
+    }
 
   if (!ptr_incr)
     return new_dataref_ptr;