On Fri, Dec 05, 2014 at 03:31:54PM -0700, Jeff Law wrote: > >Combine does not consider combining 9 into 7 because there is no LOG_LINK > >between them (the link for r88 is between 8 and 7 already). > OK, yea, that's a long standing design decision. We don't feed a single > def into multiple use sites.
There is no real reason not to do that. It doesn't increase computational complexity, although it is of course more expensive than what combine does today (it is more work, after all). And combining with a later use does not have too big a chance to succeed (since it has to keep the result of the earlier insn around always). GCC 6 or later ;-) Segher
