re PR rtl-optimization/45652 (gcc.dg/compat/scalar-by-value-3 FAILs with -O2 -fselective-scheduling2)

	PR rtl-optimization/45652
	* alias.c (get_reg_base_value): New.
	* rtl.h (get_reg_base_value): Add prototype.
	* sel-sched.c (init_regs_for_mode): Use it.  Don't use registers with
	non-null REG_BASE_VALUE for renaming.

testsuite:
	* gcc.dg/pr45652.c: New.

From-SVN: r167025