Re: An issue for the SC: horrible documentation quality of GCC

[kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)]

    We don't live in a void of one flat source tree.  While I'm not arguing
    that documentation would be better, it's still easy to find the history
    of this code.  It was added last July by Jan, in this patch:
      http://gcc.gnu.org/ml/gcc-patches/2002-07/msg00617.html

Indeed now that I see that message, I remember it.  But it doesn't answer the
question I have: why is it appropriate to have *two* constant propagation
routines within a basic block where only one (the one in cse.c) knows how to
properly apply cost functions?  At the time I saw this message, I was dubious
about this and thought I even raised the issue on the lists.

Moreover, this goes counter to the claim that was made just a few hours ago,
which is that the "local" did *not* refer to doing something that was
non-global, thus showing that there is indeed major confusion due to lack of
documentation.

However, the patch as cited in the message should *not* have been approved,
both because of the missing documentation, and because of the confusion about
the role of CSE in this task, as exemplified by the last sentence of the
posting: "I am surprised our local CSE don't know how to handle it, but I
will check it separately."  Since that "check" should have resulted in
not needing this patch, it needed to be done before the patch was approved.

My point in raising this was not to specifically get the information on
the code (as you point out, it's not hard to find the message where a 
particular piece of code was first proposed), but to address the more general
issue that there are *lots* of code that are improperly documented and it's
unreasonable to do this sort of search for *every* such function.