[PATCH] recog.c: Fix RTX unsharing in change groups - v2

["Andreas Krebbel" <krebbel at linux dot vnet dot ibm dot com>]

Hi,

this is an alternate solution to the problem described in:
http://gcc.gnu.org/ml/gcc-patches/2011-03/msg00187.html

Although I still prefer the patch above since it would make
validate_change easier to use I understand that it might add
unnecessary unsharing. The unsharing for subsequent changes is only
needed if these changes re-use parts of previous changes and insert it
at a different location in the insn and that's probably a rare case.
Swapping operands like in canonicalize_change_group is one example
which can be easily fixed.

Done with the attached patch.

Ok for mainline?

Bye,

-Andreas-



2011-03-22  Andreas Krebbel  <Andreas.Krebbel@de.ibm.com>

	* recog.c (canonicalize_change_group): Use validate_unshare_change.

Index: gcc/recog.c
===================================================================
*** gcc/recog.c.orig
--- gcc/recog.c
*************** canonicalize_change_group (rtx insn, rtx
*** 277,284 ****
        /* Oops, the caller has made X no longer canonical.
  	 Let's redo the changes in the correct order.  */
        rtx tem = XEXP (x, 0);
!       validate_change (insn, &XEXP (x, 0), XEXP (x, 1), 1);
!       validate_change (insn, &XEXP (x, 1), tem, 1);
        return true;
      }
    else
--- 277,284 ----
        /* Oops, the caller has made X no longer canonical.
  	 Let's redo the changes in the correct order.  */
        rtx tem = XEXP (x, 0);
!       validate_unshare_change (insn, &XEXP (x, 0), XEXP (x, 1), 1);
!       validate_unshare_change (insn, &XEXP (x, 1), tem, 1);
        return true;
      }
    else