------- Comment #5 from zadeck at naturalbridge dot com 2007-06-12 18:13 ------- This bug should be assigned to Mircea Namolaru <[EMAIL PROTECTED]>. I have sent him mail asking that he get a proper bugzilla id.
================================== The underlying problem is that see.c:2732 uses copy_rtx to make a copy of an insn and then hacks on it with validate_change (and it's close relatives). This is not the approved way to copy an insn. The copy_rtx function has two problems with df: 1) The copy has a basic_block, even though it is not in the insn stream, 2) The copy has the same insn_uid as the old insn. This is not legal and confuses df which keeps side info indexed by the insn_uid. There are several proper ways to make a copy of an insn: 1) call make_insn_raw (copy_rtx (PATTERN (ref))). 2) However, according to Ian Taylor, a middle end maintainer, the better thing to do would be to copy the pattern of the insn, not the insn itself and then hack on that. However, you then make a move insn and hack the modified copy so that it is right next to the move. What you should do insert the copy before the new move using one of the calls in emit_rtl such as add_insn_before. No one is supposed to hack the next and prev insn themselves. The rest of the pass appears to be df ready. Of course until it is tested it most likely does not work. And so adding some regression tests would be good. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32300
