This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug rtl-optimization/32725] Unnecessary reg-reg moves
- From: "rask at sygehus dot dk" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 11 Jul 2007 20:45:00 -0000
- Subject: [Bug rtl-optimization/32725] Unnecessary reg-reg moves
- References: <bug-32725-14600@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #4 from rask at sygehus dot dk 2007-07-11 20:45 -------
In reply to comment #2:
Reload is unable to use a register with a REG_DEAD note for an output reload.
Look at the functions find_reload_regs(), order_regs_for_reload() and
find_reg() and pay attention to how they use chain->dead_or_set and
bad_spill_regs. Several years ago, the reg sets chain->live_throughout and
chain->dead_or_set were instead chain->live_before and chain->live_after and it
would have been easy to fix something like this. I think.
But IMHO, this is something which local-alloc or global-alloc should get right
and not leave to reload.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32725