re PR target/52828 (powerpc -m32 -Os writes register saves below stack)

re PR target/52828 (powerpc -m32 -Os writes register saves below stack)

	PR target/52828
	* config/rs6000/rs6000.c (rs6000_emit_stack_tie): Rewrite with
	tie regs on destination of sets.  Delete forward declaration.
	(rs6000_emit_stack_reset): Update rs6000_emit_stack_tie calls.
	(rs6000_emit_prologue): Likewise.
	(rs6000_emit_epilogue): Likewise.  Use in place of gen_frame_tie
	and gen_stack_tie.
	(is_mem_ref): Use tie_operand to recognise stack ties.
	* config/rs6000/predicates.md (tie_operand): New.
	* config/rs6000/rs6000.md (restore_stack_block): Generate new
	stack tie rtl.
	(restore_stack_nonlocal): Likewise.
	(stack_tie): Update.
	(frame_tie): Delete.

From-SVN: r186397