[PPL-devel] Fwd: ppl 0.11.2 vs llvm

[Roberto Bagnara]

On 08/03/11 16:09, Jack Howarth wrote:
> Roberto,
>     The complete set of failures reported for ppl-0.11.2 when built under
> Xcode 4.1's clang are...
>
> Box
> ---
> affineimage1
> frompolyhedron1
> frompolyhedron2
> propagateconstraints2
> refinewithconstraint1
> nnc_frompolyhedron1
>
> BD_Shape
> --------
> closure1
>
> Again this appears to be an issue with the llvm backend as both llvm-gcc and clang
> exhibit these failures (and both use different llvm releases for their backends).
> I'll look into reproducing these failures under Linux.
>          Jack

Hi Jack,

thanks for your report.  I have just compiled the Git version of PPL
(master branch) with clang, and fixed a few warning (all were innocuous).

I am now running `make check' under Linux, using a version of clang
compiled with assertions (so compilation proceeds very slowly).

Enea Zaffanella, a fellow PPL developer, advanced the hypothesis
that the warning

clang: warning: argument unused during compilation: '-frounding-math'

may be the cause of the problem.  Indeed, the failures you observe are
compatible with this hypothesis: can you please check whether the Box
and BD_Shape failures occur for instantiations with floating point numbers?
If really clang has no way to obtain the effect of `-frounding-math',
then we have to detect clang in `configure' and disable all the
floating-point instantiations.
Thanks again,

    Roberto

-- 
Prof. Roberto Bagnara
Applied Formal Methods Laboratory
Department of Mathematics, University of Parma, Italy
http://www.cs.unipr.it/~bagnara/
mailto:bagnara at cs.unipr.it