re PR rtl-optimization/45352 (ICE: in reset_sched_cycles_in_current_ebb, at sel-sched.c:7058)

        PR rtl-optimization/45352
        * sel-sched.c (find_best_expr): Do not set pneed_stall when
        the variable_issue hook is not implemented.
        (fill_insns): Remove dead variable stall_iterations.
        (init_seqno_1): Force EBB start for resetting sched cycles on any
        successor blocks of the rescheduled region.
        (sel_sched_region_1): Use bitmap_bit_p instead of bitmap_clear_bit.
        (reset_sched_cycles_in_current_ebb): Add debug printing.
        New variable issued_insns.  Advance state when we have issued
        issue_rate insns.

        gcc.dg/pr45352.c, gcc.dg/pr45352-1.c, gcc.dg/pr45352-2.c: New tests.
        gcc.target/i386/pr45352.c, gcc.target/i386/pr45352-1.c,
        gcc.target/i386/pr45352-2.c: New tests.

From-SVN: r166429