RFA: patch to fix PR55116

[Vladimir Makarov]

   H.J. in

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55116

   reported an interesting address

(and:DI (subreg:DI (plus:SI (ashift:SI (reg:SI 96 [ glob_vol_int.22 ])
                 (const_int 2 [0x2]))
             (symbol_ref:SI ("glob_vol_int_arr") <var_decl 
0x7ffff03c2720 glob_vol_int_arr>)) 0)
     (const_int 4294967295 [0xffffffff]))

   which can not be correctly extracted.  Here `and' with `subreg' 
behaves as an address mutation.

   The following patch fixes the problem.

Ok to commit, Richard?

2012-10-29  Vladimir Makarov  <vmakarov@redhat.com>

         PR middle-end/55116
         * rtlanal.c (strip_address_mutation): Add SUBREG case.



Index: rtlanal.c
===================================================================
--- rtlanal.c   (revision 192942)
+++ rtlanal.c   (working copy)
@@ -5459,6 +5459,11 @@ strip_address_mutations (rtx *loc, enum
        else if (code == AND && CONST_INT_P (XEXP (*loc, 1)))
         /* (and ... (const_int -X)) is used to align to X bytes.  */
         loc = &XEXP (*loc, 0);
+      else if (code == SUBREG
+              && ! REG_P (XEXP (*loc, 0)) && ! MEM_P (XEXP (*loc, 0)))
+       /* (subreg (operator ...) ...) usually inside and is used for
+          mode conversion too.  */
+       loc = &XEXP (*loc, 0);
        else
         return loc;
        if (outer_code)