It is required due to CGAL. While we do not use rounding-sensitive parts
of CGAL (the Voronoi diagram construction is safe in that regard),
unfortunately CGAL checks during library initialization that
-frounding-math is active. So short of an invasive patching of CGAL this
is the simplest solution.

-frounding-math only affects the optimization, and is portable for all
architectures supported by GCC.

On 29.11.2013 18:35, slava77 wrote:
> In RecoHI/HiJetAlgos/plugins/BuildFile.xml:
> 
>> @@ -4,12 +4,8 @@
>>  <use   name="FWCore/ParameterSet"/>
>>  <use   name="RecoHI/HiJetAlgos"/>
>>  <use   name="DataFormats/JetReco"/>
>> +<Flags CXXFLAGS="-frounding-math"/>
> 
> Is this required here?
> @smuzaffar <https://github.com/smuzaffar> @ktf <https://github.com/ktf>
> Will this work properly on all architecture that we support?
> 
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/cms-sw/cmssw/pull/1564/files#r8005983>.
>