[petsc-dev] CFLAGS and COPTFLAGS

[Barry Smith]

On Jan 17, 2014, at 9:46 PM, Jed Brown <jed at jedbrown.org> wrote:

> Barry Smith <bsmith at mcs.anl.gov> writes:
> 
>>   
>>>> 
>>>>  We can look for -O%d , are there other things to look for?  This seems easy enough to add.
>>> 
>>> -ftree-vectorize, -fast, -qhot -qsimd=auto
>> 
>>   So if they pass -fast then we simply don’t set any optimization flags ourself? We could do that.
> 
> My point was that there are *lots* of optimization flags, with new ones
> every release from every vendor.  We could test for a few, but can never
> be comprehensive.  Do we want to be in this business?

   Do people really set some of the above and not set the -O%d one at the same time?

   My plan was if CFLAGS contained a -O[%d] then we turn off automatic setting of optimization flags. Why would this not work?

   I agree with you we currently have a problem but I want a solution better than the community.

   Barry