Was: Debug optimized code; Now: How many compiler bugs have you seen?

Chris F Clark <cfc@shell01.TheWorld.com>
Wed, 24 Sep 2008 12:46:15 -0400

          From comp.compilers

Related articles
Debug optimized code linuxkaffee_@_gmx.net (Stephan Ceram) (2008-09-16)
Re: Debug optimized code gneuner2@comcast.net (George Neuner) (2008-09-20)
Re: Debug optimized code sh006d3592@blueyonder.co.uk (Stephen Horne) (2008-09-22)
Re: Debug optimized code gneuner2@comcast.net (George Neuner) (2008-09-23)
Was: Debug optimized code; Now: How many compiler bugs have you seen? cfc@shell01.TheWorld.com (Chris F Clark) (2008-09-24)
Re: Was: Debug optimized code; Now: How many compiler bugs have you se ArarghMail809@Arargh.com (2008-09-24)
Re: Debug optimized code; Now: How many compiler bugs have you seen? armelasselin@hotmail.com (Armel) (2008-09-24)
Re: Was: Debug optimized code; Now: How many compiler bugs have you se n.pipenbrinck@cubic.org (Nils) (2008-09-25)
Re: Was: Debug optimized code; Now: How many compiler bugs have you se sh006d3592@blueyonder.co.uk (Stephen Horne) (2008-09-25)
Re: Was: Debug optimized code; Now: How many compiler bugs have you se gneuner2@comcast.net (George Neuner) (2008-09-25)
Re: Was: Debug optimized code; Now: How many compiler bugs have you se dot@dotat.at (Tony Finch) (2008-09-25)
[5 later articles]
| List of all articles for this month |

From: Chris F Clark <cfc@shell01.TheWorld.com>
Newsgroups: comp.compilers
Date: Wed, 24 Sep 2008 12:46:15 -0400
Organization: The World Public Access UNIX, Brookline, MA
References: 08-09-076 08-09-105 08-09-110 08-09-115
Keywords: optimize, debug
Posted-Date: 24 Sep 2008 14:44:17 EDT

George Neuner <gneuner2@comcast.net> writes:


> Not to mention that the compiler itself is more likely to have
> strangely interacting bugs in its higher optimization levels.


People often mention this and having workied on compilers I've seen my
shared of bugs (from the inside). However, as a compiler customer I
can only recall two times in my career where I've actually encountered
a bug that was in the compiler and not in "my" code (the code I was
working on).


One case, was a case where a specific model of a machine had a special
hardware flaw and it wasn't patched over in the compiler I was using.
The other case was a simple blatant bug where the compiler simply
dropped the code for a line that said x = x * 2; (the work around was
to recoded it as x = x + x;).


However, beyond those two cases I've never (as a user) experienced a
real compiler bug. I've seen lots of cases where the compiler exposed
aliasing problems and places where the code was expecting things to be
order in specific ways not guaranteed by the standard, but only those
two bugs.


So, I wonder, how many of you have experienced real compiler bugs,
that you could verify was the compilers fault and not just "mysterious
behavior" that could be fixed by changing the optimizer/debugger
level?


Just curious,
-Chris


******************************************************************************
Chris Clark Internet: christopher.f.clark@compiler-resources.com
Compiler Resources, Inc. or: compres@world.std.com
23 Bailey Rd Web Site: http://world.std.com/~compres
Berlin, MA 01503 voice: (508) 435-5016
USA fax: (978) 838-0263 (24 hours)


Post a followup to this message

Return to the comp.compilers page.
Search the comp.compilers archives again.