http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54128
--- Comment #15 from Alexandre Oliva <aoliva at gcc dot gnu.org> 2012-12-21 01:52:47 UTC --- Steve, the patch referenced in comment 12 makes sense to me. I agree with Jakub's comment that the first hunk shouldn't make any difference, because debug insns don't have DEFs, but it doesn't hurt and might marginally speed things up, so I'd go with the patch as it is. As for enabling debug temp binds to reference unused/dead REGs when there aren't intervening insns between the death and the debug use, the idea makes sense to me, but I'm concerned about complications, particularly in case of adjustments necessary to the debug insn because of changes to the REG at its death point. It might require algorithmic changes because most algorithms aren't expected to need to make adjustments outside the live ranges of the REG. I'd proceed with care.