[Python-Dev] pyc files, constant folding and borderline portability issues
Mark Dickinson
dickinsm at gmail.com
Mon Apr 6 21:30:57 CEST 2009
[Antoine]
> - Issue #5593: code like 1e16+2.9999 is optimized away and its result stored as
> a constant (again), but the result can vary slightly depending on the internal
> FPU precision.
[Guido]
> I would just not bother constant folding involving FP, or only if the
> values involved have an exact representation in IEEE binary FP format.
+1 for removing constant folding for floats (besides conversion
of -<literal>). There are just too many things to worry about:
FPU rounding mode and precision, floating-point signals and flags,
effect of compiler flags, and the potential benefit seems small.
Mark
More information about the Python-Dev
mailing list