REG_UNUSED notes for CLOBBERs?

[Eric Botcazou]

> That's what I believe, too. Still, combine appears to add REG_UNUSED
> notes for clobbers intentionally. Do you know why it does that?

Hmm, right, it apparently clearly wants to immediately close the "live" ranges 
it creates by adding new clobbers.  And, indeed, regrename.c for example uses 
these CLOBBER/REG_UNUSED pairs to compute live ranges for non-operands (the 
pass does its own forward scan of the insn stream).  So DF's choice might have 
been made explicitly after all...

-- 
Eric Botcazou