modulo-sched: fix bootstrap compare-debug issue

modulo-sched: fix bootstrap compare-debug issue

This patch removes all debug insns from DDG analysis.  It fixes bootstrap
comparison failure on powerpc64le when running with -fmodulo-sched enabled.

	* ddg.c (create_ddg_dep_from_intra_loop_link): Remove assertions.
	(create_ddg_dep_no_link): Likewise.
	(add_cross_iteration_register_deps): Move debug instruction check.
	Other minor refactoring.
	(add_intra_loop_mem_dep): Do not check for debug instructions.
	(add_inter_loop_mem_dep): Likewise.
	(build_intra_loop_deps): Likewise.
	(create_ddg): Do not include debug insns into the graph.
	* ddg.h (struct ddg): Remove num_debug field.
	* modulo-sched.c (doloop_register_get): Adjust condition.
	(res_MII): Remove DDG num_debug field usage.
	(sms_schedule_by_order): Use assertion against debug insns.
	(ps_has_conflicts): Drop debug insn check.

testsuite:

    	* gcc.c-torture/execute/pr70127-debug-sms.c: New test.
    	* gcc.dg/torture/pr87197-debug-sms.c: New test.