[Bug tree-optimization/49452] [4.7 regression] comp-goto-2.c regresses in testing

["carrot at google dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49452

--- Comment #23 from Carrot <carrot at google dot com> 2011-09-16 06:57:15 UTC ---
(In reply to comment #21)
> > All callee saved registers should never changed after function call. Here fp
> > has been changed is not because it is after a function call, it is because it
> > is after the target of non local goto. I'm not familiar with the implementation
> > of non local goto, but I guess there is some convention/protocol defines which
> > registers may be changed after the target of a non local goto.
> 
> That's not the problem.  The problem is that the blockage isn't honored.

It seems postreload.c should be changed to the following to avoid combining

--- postreload.c    (revision 178904)
+++ postreload.c    (working copy)
@@ -1312,7 +1312,7 @@ reload_combine (void)
      is and then later disable any optimization that would cross it.  */
       if (LABEL_P (insn))
     last_label_ruid = reload_combine_ruid;
-      else if (BARRIER_P (insn))
+      else if (BARRIER_P (insn) || BLOCKAGE_P (insn))
     for (r = 0; r < FIRST_PSEUDO_REGISTER; r++)
       if (! fixed_regs[r])
           reg_state[r].use_index = RELOAD_COMBINE_MAX_USES;

BLOCKAGE_P (insn) is used to detect if insn is a blockage insn, is there any
available function/macro that implement this functionality?