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Subject: RE: possible compiler optimization error
Date: Thu, 28 Jun 2007 14:37:10 -0400
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From: "Frederich, Eric P21322" <eric DOT frederich AT siemens DOT com>
To: "Dave Korn" <dave DOT korn AT artimi DOT com>, <cygwin AT cygwin DOT com>
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> From: cygwin-owner AT cygwin DOT com On Behalf Of Dave Korn
> Sent: Thursday, June 28, 2007 1:39 PM
> To: cygwin AT cygwin DOT com
> Subject: RE: possible compiler optimization error
> 
> On 28 June 2007 18:19, Frederich, Eric P21322 wrote:
> 
>   Your code has a bug, most likely an uninitialised or otherwise stray
> pointer, but could be anything that causes undefined 
> behaviour.  It works on
> Linux/Solaris by good fortune, because whatever memory 
> addresses you're
> stomping all over just happen to be free and safe to stomp on on those
> platforms, whereas windows systems have different process 
> space layout 

During development of this program I used Valgrind on Linux to detect
memory allocation and un-initialized pointer type of errors.  I do not
believe this is the case.

> Now, there /could/ be a compiler bug, but unless you can 
> present us with a
> testcase that we can compile ourselves and test out, it's not 
> going to be easy
> to help you.  Fragmentary code snippets aren't useful.  For 
> advice on how to
> write a really good compiler bug report, see the guidelines at

Yes, I do realize this.  I figured that describing the behavior would be
enough to diagnose the problem without having to cut down an 8,000 line
program into a concise example.  It turns out that it was and Brian
Dessent suggested some more compiler flags to help with floating point
accuracy, -ffloat-store.

Thanks for your help.

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