This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug target/64331] regcprop propagates registers noted as REG_DEAD
- From: "ebotcazou at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Wed, 17 Dec 2014 15:12:30 +0000
- Subject: [Bug target/64331] regcprop propagates registers noted as REG_DEAD
- Auto-submitted: auto-generated
- References: <bug-64331-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64331
--- Comment #5 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
> Is it just REG_USED/REG_DEAD notes, or is register liveliness
> (df_regs_ever_live_p etc..) also not guaranteed to be up to date?
These REG_UNUSED/REG_DEAD notes are special because they are not maintained
incrementally by the DF framework, i.e. the insn manipulation routines don't
cause them to be updated, so they are really valid only just after they are
recomputed. The rest of the liveness info is updated incrementally (if DF is
asked to).