Re: mingw32 floating point diff - Mailing list pgsql-hackers

From Tom Lane
Subject Re: mingw32 floating point diff
Date
Msg-id 1469.1566482103@sss.pgh.pa.us
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In response to mingw32 floating point diff  (Peter Eisentraut <peter.eisentraut@2ndquadrant.com>)
Responses Re: mingw32 floating point diff  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Peter Eisentraut <peter.eisentraut@2ndquadrant.com> writes:
> On 2019-08-20 14:59, Peter Eisentraut wrote:
>> Running the regression tests on mingw32, I get the following diff in
>> circle.out:
...
> OK, the problem isn't the new output routines.  The result of the
> computations is actually different.  The test itself is new in PG12.
> The difference in output is due to the mingw32 target using -mfpmath=387
> by default.  If you build with -mfpmath=sse -msee, the tests pass again.

Hm, so presumably we could replicate this on other Intel-oid platforms
by changing compiler switches?  (I haven't tried.)

> Do we care to do anything about this?  Pick slightly different test data
> perhaps?

Picking different test data might be a good "fix".  Alternatively, we
could try to figure out where the discrepancy is arising and adjust
the code --- but that might be a lot more work than it's worth.

            regards, tom lane



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