Re: Do we still need PowerPC-specific timestamp_is_current/epoch?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp>
Cc: lockhart(at)alumni(dot)caltech(dot)edu, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Do we still need PowerPC-specific timestamp_is_current/epoch?
Date: 2001-03-13 01:47:20
Message-ID: 13649.984448040@sss.pgh.pa.us
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Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp> writes:
> After further research, I remembered that we used to have "DB_MIN
> check" in configure back to 6.4.2:
> I don't know wht it was removed,

Hmm. Digging in the CVS logs shows that it was removed by Bruce in
configure.in version 1.262, 1999/07/18, with the unedifying log message
"configure cleanup".

A guess is that he took it out because it wasn't being used anywhere.

> but I think we'd better to revive the checking and replace
> #if defined(linux) && defined(__powerpc__)
> with
> #ifdef HAVE_DBL_MIN_PROBLEM
> What do you think?

I think that is a bad idea, since that code is guaranteed to fail on any
machine where the representation of double is at all different from a
PPC's. (Even if you are willing to assume that the entire world uses
IEEE floats these days, what of endianness?)

We could revive the configure test and do

#if defined(HAVE_DBL_MIN_PROBLEM) && defined(__powerpc__)

However, I really wonder whether there is any point. It may be worth
noting that the original version of the patch read "#if ... defined(PPC)".
It's quite likely that the current test, "... defined(__powerpc__)",
doesn't even fire on the old compiler that the patch is intended for.
If so, this is dead code and has been since release 6.5.

regards, tom lane

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