| From: | Heikki Linnakangas <hlinnakangas(at)vmware(dot)com> |
|---|---|
| To: | Greg Stark <stark(at)mit(dot)edu> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Bruce Momjian <bruce(at)momjian(dot)us>, Robert Haas <robertmhaas(at)gmail(dot)com>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Xi Wang <xi(dot)wang(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: [RFC] overflow checks optimized away |
| Date: | 2013-11-29 20:36:00 |
| Message-ID: | 5298FAB0.5010203@vmware.com |
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| Lists: | pgsql-hackers |
On 11/29/2013 10:06 PM, Greg Stark wrote:
> On Fri, Nov 29, 2013 at 7:39 PM, Greg Stark <stark(at)mit(dot)edu> wrote:
>>
>> Just as an update I did get gcc to do the wrong thing on purpose. The
>> only overflow check that the regression tests find missing is the one
>> for int8abs() ie:
>
>
> Also, one of the places GCC warns about optimizing away an overflow
> check (with -fno-wrapv) is inside the localtime.c file from the tz
> library. I fixed it in my patch but in fact I checked and it's already
> fixed upstream so I'm wondering whether you expect to merge in an
> updated tz library? Is there anything surprising about the process or
> do you just copy in the files? Would you be happy for someone else to
> do it?
IIRC some files can be copied directly, but not all. Might be easiest to
generate a diff between the last version in PostgreSQL and the latest
upstream version, and apply that.
- Heikki
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