tree-ssa-math-opts.c (find_bswap_or_nop_1): Fix creation of MARKER_BYTE_UNKNOWN markers when handling casts.

2014-10-21  Thomas Preud'homme  <thomas.preudhomme@arm.com>

    gcc/
    * tree-ssa-math-opts.c (find_bswap_or_nop_1): Fix creation of
    MARKER_BYTE_UNKNOWN markers when handling casts.

    gcc/testsuite/
    * gcc.dg/optimize-bswaphi-1.c: New bswap pass test.

From-SVN: r216511