PR target/23774
* config/rs6000/rs6000.md (restore_stack_block): Write the backchain
word before changing the stack pointer. Use gen_frame_mem for MEMs.
Use UNSPEC_TIE to prevent insn scheduling reordering the insns.
(restore_stack_nonlocal): Likewise.
(save_stack_nonlocal): Use template to emit insns, and gen_frame_mem.
From-SVN: r104206
