PR rtl-optimization/23478
	* local-alloc.c (struct qty): Add n_throwing_calls_crossed field.
	(alloc_qty): Initialize it.
	(update_equiv_regs): Clear REG_N_THROWING_CALLS_CROSSED.
	(combine_regs): Combine also n_throwing_calls_crossed fields.
	(find_free_reg): Don't attempt to caller-save pseudos crossing
	calls that might throw.
	* global.c (struct allocno): Add throwing_calls_crossed field.
	(global_alloc): Revert 2005-08-22 change.  Initialize
	throwing_calls_crossed.
	(find_reg): Don't attempt to caller-save pseudos crossing calls that
	might throw.

From-SVN: r103718