* rtl.h (enum reg_note): Add REG_MAYBE_DEAD.
* rtl.c (reg_note_name): Add REG_MAYBE_DEAD.
* flow.c (propagate_one_insn): Allow deletion of prologue/epilogue
insns if they have a REG_MAYBE_DEAD note attached.
* config/rs6000/rs6000.c (rs6000_maybe_dead): New function.
(rs6000_emit_load_toc_table): TOC loads may go dead.

From-SVN: r35414