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Re: SSA_NAMES: should there be an unused, un-free limbo?


I may be missing something, but I don't think that is the interesting
issue here.

I agree.


I think the issue is whether we want to have a way to see all
currently valid SSA_NAMEs.  Right now we can have SSA_NAMEs in the
list which are no longer used, and we have no way to tell whether they
are used or not.  Thus the only way to see all valid SSA_NAMEs is to
walk the code.

If that is acceptable, then there is no issue here.  If that is not
acceptable, then we need to fix the code to correctly mark SSA_NAMEs
which are no longer used.  Whether we recycle the memory in the unused
SSA_NAMEs is a separate (and less interesting) discussion.

IMHO, it's not acceptable, because it leaves no way to do DFS walks
that don't involve kludges and hacks.
Ian


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