Totally bizarre error, requesting assistance

[Iain Buclaw via Digitalmars-d]

On 19 Sep 2014 05:50, "Koz Ross via Digitalmars-d" <
digitalmars-d at puremagic.com> wrote:
>
> I don't know if this is the right place to ask, but I figured it was
worth a try. Basically, I'm getting totally bizarre behaviour from my code,
which I have put in a repo at
https://gitorious.org/tournament-tree/tournament-tree/source/545460fb9d760b6bfa5bc74deb7b69d79ec70541
:
>
> To replicate the error, simply run 'make profile' from the project
directory. It should fail (claiming an enforcement error on node.d, line
50). Then, go to tournament.d, and uncomment line 33. Then, try 'make
profile' again, and it won't have the same issue. I've been working all day
to try and isolate the source of the problem, across multiple machines, and
I've had no luck. This is the most isolation I've managed.
>
> I would really appreciate any and all help, as this is something that
totally baffles me. I know this is a lot of code, and it's probably quite
hideous, but it would help me a lot if someone could at least suggest as to
where the source of the problem lies.
>
> I already am aware that the failure is caused by an overflow, but its
source is completely unclear, and I never get overflows when that one
writeln statement in tournament.d is executed (hence my confusion).
>
> I'm running Manjaro GNU/Linux, and my gdc version is 4.9.1. I have a
64-bit OS.

What flags are you using to build?  And is this a package you installed
from your distribution?

Recently in upstream, I've turned on -fwrapv by default so that the backend
handles overflow as precisely defined, rather than optimising aggressively
by pretending it never happens.

http://bugzilla.gdcproject.org/show_bug.cgi?id=141

It may be a good idea to add this flag to your build script if you are
using an earlier version of gdc.

Iain.
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