Ping: RFA: Improve doloop_begin support

[Joern Rennecke]

2012-09-26  J"orn Rennecke  <joern.renne...@arc.com>

        * loop-doloop.c (doloop_modify): Pass doloop_end pattern to
        gen_doloop_begin.
        * loop-doloop.c (doloop_optimize): Pass flag to indicate if loop is
        entered at top to gen_doloop_end.
        * config/arm/thumb2.md (doloop_end): Accept extra operand.
        * config/bfin/bfin.md (doloop_end): Likewise.
        * config/c6x/c6x.md (doloop_end): Likewise.
        * config/ia64/ia64.md (doloop_end): Likewise.
        * config/mep/mep.md (doloop_begin, doloop_end): Likewise.
        * config/rs6000/rs6000.md (doloop_end): Likewise.
        * config/s390/s390.md (doloop_end): Likewise.
        * config/sh/sh.md (doloop_end): Likewise.
        * config/spu/spu.md (doloop_end): Likewise.
        * config/tilegx/tilegx.md (doloop_end): Likewise.
        * config/tilepro/tilepro.md (doloop_end): Likewise.
        * doc/md.texi (doloop_end): Document new operand.

http://gcc.gnu.org/ml/gcc-patches/2012-09/msg01807.html