The POSIX standard says this about the exp(3) function:
If x is -Inf, +0 shall be returned.
At least on my Linux box, our version does no such thing:
regression=# select exp('-inf'::float8);
ERROR: value out of range: underflow
Does anyone disagree that that's a bug? Should we back-patch
a fix, or just change it in HEAD? Given the lack of user
complaints, I lean a bit towards the latter, but am not sure.
regards, tom lane