re PR rtl-optimization/60651 (Mode switching instructions are sometimes emitted in...

re PR rtl-optimization/60651 (Mode switching instructions are sometimes emitted in the wrong order)

gcc:
        PR rtl-optimization/60651
        * mode-switching.c (optimize_mode_switching): Make sure to emit
        sets of a lower numbered entity before sets of a higher numbered
        entity to a mode of the same or lower priority.
        When creating a seginfo for a basic block that starts with a code
        label, move the insertion point past the code label.
        (new_seginfo): Document and enforce requirement that
        NOTE_INSN_BASIC_BLOCK only appears for empty blocks.
        * doc/tm.texi.in: Document ordering constraint for emitted mode sets.
        * doc/tm.texi: Regenerate.
gcc/testsuite:
        PR rtl-optimization/60651
        * gcc.target/epiphany/mode-switch.c: New test.

From-SVN: r209312