re PR middle-end/53708 (Many failures of the objc tests with -O3 -fnext-runtime and -m32)

2012-06-19  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/53708
	* tree-vect-data-refs.c (vect_can_force_dr_alignment_p): Preserve
	user-supplied alignment and alignment of decls with the used
	attribute.

From-SVN: r188771

gcc/ChangeLog

+2012-06-19  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/53708
+	* tree-vect-data-refs.c (vect_can_force_dr_alignment_p): Preserve
+	user-supplied alignment and alignment of decls with the used
+	attribute.
+
 2012-06-18  Lawrence Crowl  <crowl@google.com>
 
 	* timevar.def (TV_PHASE_GENERATE): Rename to TV_PHASE_LATE_ASM.

gcc/tree-vect-data-refs.c

@@ -4731,6 +4731,12 @@ vect_can_force_dr_alignment_p (const_tree decl, unsigned int alignment)
   if (TREE_ASM_WRITTEN (decl))
     return false;
 
+  /* Do not override explicit alignment set by the user or the alignment
+     as specified by the ABI when the used attribute is set.  */
+  if (DECL_USER_ALIGN (decl)
+      || DECL_PRESERVE_P (decl))
+    return false;
+
   if (TREE_STATIC (decl))
     return (alignment <= MAX_OFILE_ALIGNMENT);
   else