[Bug middle-end/36858] New: Incorrect alignment attribute on stack parameter

["hjl dot tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

locate_and_pad_parm has

  where_pad = FUNCTION_ARG_PADDING (passed_mode, type);
  boundary = FUNCTION_ARG_BOUNDARY (passed_mode, type);
  locate->where_pad = where_pad;
  locate->boundary = boundary;

  /* Remember if the outgoing parameter requires extra alignment on the
     calling function side.  */
  if (boundary > PREFERRED_STACK_BOUNDARY)
    boundary = PREFERRED_STACK_BOUNDARY;

When boundary > PREFERRED_STACK_BOUNDARY, boundary is capped
to PREFERRED_STACK_BOUNDARY.  But locate->boundary has the wrong
value. The following patch should correct this:

Index: function.c
===================================================================
--- function.c  (revision 137896)
+++ function.c  (working copy)
@@ -3258,13 +3258,13 @@ locate_and_pad_parm (enum machine_mode p
     = type ? size_in_bytes (type) : size_int (GET_MODE_SIZE (passed_mode));
   where_pad = FUNCTION_ARG_PADDING (passed_mode, type);
   boundary = FUNCTION_ARG_BOUNDARY (passed_mode, type);
+  if (boundary > PREFERRED_STACK_BOUNDARY)
+    boundary = PREFERRED_STACK_BOUNDARY;
   locate->where_pad = where_pad;
   locate->boundary = boundary;

   /* Remember if the outgoing parameter requires extra alignment on the
      calling function side.  */
-  if (boundary > PREFERRED_STACK_BOUNDARY)
-    boundary = PREFERRED_STACK_BOUNDARY;
   if (crtl->stack_alignment_needed < boundary)
     crtl->stack_alignment_needed = boundary;


-- 
           Summary: Incorrect alignment attribute on stack parameter
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: hjl dot tools at gmail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36858