regcprop and REG_DEAD

[Eric Botcazou]

> Question: that code doesn't appear to touch REG_DEAD notes at all.  Is that
> right?  From the definition of REG_DEAD, it seems that rewriting a later
> insns to use register x means that a preceding (REG_DEAD x) needs to be
> deleted.  Or moved to the later insn, perhaps.

If the pass doesn't consume REG_DEAD/REG_UNUSED notes, it doesn't have to keep 
them up-to-date.  Instead, passes that consume them must df_note_add_problem() 
on entry.  For the generic reorg (delay slot filling) pass, this is done in 
rest_of_pass_free_cfg.

-- 
Eric Botcazou