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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Dean Rasheed <dean.a.rasheed@gmail.com>
cc: Yugo NAGATA <nagata@sraoss.co.jp>,
        PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
        Dave Page <dpage@pgadmin.org>
Subject: Re: Numeric x^y for negative x
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Comments: In-reply-to Dean Rasheed <dean.a.rasheed@gmail.com>
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Dean Rasheed <dean.a.rasheed@gmail.com> writes:
> So the "test for overflow by reverse-conversion" obviously isn't
> working as intended, and it's going through power_var_int() when it
> shouldn't. I don't think there's anything wrong with that code, so I
> think this is a compiler bug.

Yeah, looks like one.

> I guess the best thing to do is just test the value against
> PG_INT32_MIN/MAX, which is what int84() does. There are 2 other places
> in numeric.c that use similar code to check for int16/32 overflow, so
> it's possible that they're broken in the same way on that platform,
> but they aren't covered by the regression tests, so it's also possible
> that they're OK. Anyway, something like the attached seems likely to
> be safer.

Looks plausible by eyeball (I've not tested).

			regards, tom lane