AW: AW: Could turn on -O2 in AIX

From: Zeugswetter Andreas SB <ZeugswetterA(at)wien(dot)spardat(dot)at>
To: "'Tom Lane'" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: "'pgsql-hackers(at)postgresql(dot)org'" <pgsql-hackers(at)postgresql(dot)org>
Subject: AW: AW: Could turn on -O2 in AIX
Date: 2000-11-10 21:07:20
Message-ID: 11C1E6749A55D411A9670001FA687963368109@sdexcsrv1.f000.d0188.sd.spardat.at
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> There is a special case in nabstime.h for AIX, which imho
> got swapped. The normal case for me would be INT_MIN
> and not the 0x80000001.
> There is a comment that I don't understand at all given the below
> source code:
>
> /*
> * AIX considers 2147483648 == -2147483648 (since they have
> the same bit
> * representation) but uses a different sign sense in a comparison to
> * these integer constants depending on whether the constant is signed
> * or not!
> */
> #if defined (_AIX)
> #define NOSTART_ABSTIME ((AbsoluteTime) INT_MIN)
> #else
> #define NOSTART_ABSTIME ((AbsoluteTime) 0x80000001)
> /* -2147483647 (- 2^31) */
> #endif
>
> But that is unfortunately not the problem. Looks like yet
> another broken compiler to me :-(

Ok, the comparison ((int) time) > ((int) 0x80000001) is the problem.
Reading the comment again and again, I have come to the conclusion,
that the intent was originally to avoid INT_MIN on AIX.

My solution would be to use INT_MIN for all ports, which has the advantage
that the above problematic comparison can be converted to !=,
since no integer will be smaller than INT_MIN.

Please apply the patch and all works well.

Thanks
Andreas

Attachment Content-Type Size
aix_O2.patch application/octet-stream 3.3 KB

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