A question about df

[Revital1 Eres]

Hello,

While testing a patch for the SMS I got an ICE which seems
to be related to the fact we build def-use chains only
and not use-def chains.  (removed in the following patch -
http://gcc.gnu.org/ml/gcc-patches/2006-12/msg01682.html)

The problem arises when we delete an insn from the df that contains a
use but do not update the def-use chain of it's def as we do not have
the use-def chain to reach it's def, This later causes a problem when
we try to dump the def-use chain of it's def.

So, it seems that when asking for only def-use problem and later dump
the function we should ask for use-def problem as well to avoid cases
like the above.

Thanks,
Revital