re PR rtl-optimization/48302 (ICE: SIGSEGV in reposition_prologue_and_epilogue_notes (function.c:5662) with -fcrossjumping -fselective-scheduling2)

	PR rtl-optimization/48302
	* sel-sched-ir.h (sel_add_loop_preheaders): Update prototype.
	* sel-sched-ir.c (sel_add_loop_preheaders): Add 'bbs' argument.  Use
	it to record added preheader blocks.
	* sel-sched.c (setup_current_loop_nest): Add 'bbs' argument.  Pass it
	on to sel_add_loop_preheaders.
	(sel_region_init): Move call to setup_current_loop_nest after
	sel_init_bbs.

testsuite:
	* g++.dg/opt/pr48302.C: New.

From-SVN: r172176