sibcall.c (optimize_sibling_and_tail_recursive_calls): Call purge_mem_unchanging_flag on all instructions...

	* sibcall.c (optimize_sibling_and_tail_recursive_calls): Call
	purge_mem_unchanging_flag on all instructions, not just on those
	before NOTE_INSN_FUNCTION_BEG.

From-SVN: r46091