[cfe-users] Clang9 UBSan and GMP

[David Blaikie via cfe-users]

Yeah, coming across compiler bugs does happen - but more often it's bugs in
input programs. (one of the reasons compiler engineers aren't likely to
jump on reproducing and reducing misbehaving programs, because on the odds,
it's not a bug in the compiler)

On Fri, Oct 25, 2019 at 3:12 PM Hans Åberg <haberg-1 at telia.com> wrote:

> The sources are available at [1]; it is written in C, not C++. I was was
> hoping that that something like UBSan would shed light on it, but the
> original question is answered: it changes optimization. The GMP developers
> say that they have caught some compiler bugs, but that is hard to do and
> time consuming.
>
> 1. https://gmplib.org
>
>
> > On 25 Oct 2019, at 23:38, David Blaikie <dblaikie at gmail.com> wrote:
> >
> > It's hard to know if it's the compiler's fault without a test case - due
> to the nature of undefined behavior and other things (implementation
> defined behavior and unspecified behavior) in C++, that the program behaves
> as expected with another compiler or another set of flags doesn't give a
> strong indication as to where the problem is (in the code, in one of the
> compilers, etc).
> >
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-users/attachments/20191025/d3b30d7f/attachment.html>