On Mar 16, 2005 05:11 PM, Mostafa Hagog <[EMAIL PROTECTED]> wrote: > > > > > [EMAIL PROTECTED] (Richard Kenner) wrote on 16/03/2005 17:27:59: > > > REG_NOTE (NONNEG) > > REG_NOTE (NO_CONFLICT) > > REG_NOTE (UNUSED) > > mustn't be copied > > describe a fact about other instructions so this > > may change if copied. > > > > Tricky. Often UNUSED means that we're allocating a psuedo for some > temporary > > which we know isn't used. > > I suppose this is a function level information - meaning: the rgister is > not used all over the > function- so we can (and should) copy it. > > > > > REG_NOTE (CC_SETTER) > > REG_NOTE (CC_USER) > > I suppose that using CC0 is possible only in branch > > instructions (correct > > me if I am wrong) > > > > It can also be used in "scc" insns. > > This is interesting, so there could be cases were want to copy CC register > when doing SMS. what happens if we want to move the set of a CC to > another iteration of the loop ? or the use of the CC ? > but usually this is couldn't happen in a simple loop, right? the use of CC > is > eventually used in a branch, or there is something that I am missing ?
IIRC these notes are for CCO, and you have to move the CC setter and user together. Actually I think SMS for CC0 targets is Just Silly to do at all ;-) Gr. Steven the CC setter is always th
