* flow.c (struct propagate_block_info): Add new_dead, new_live.
(propagate_block): Initialize them. Use them in parallel instead
of one tmp variable, ie revert much of the 0408 and 0407 functional
changes, but keep the structural changes.
(mark_set_regs): Take new_dead from propagate_block_info instead.
(mark_set_1, mark_set_reg): Likewise.
(mark_used_regs): Likewise with new_live.
(mark_used_reg): Likewise. Revert 0408 change.