Re: 7+ days of dogfood

	From sgk_at_troutmask.apl.washington.edu Sun Feb 10 19:06:10 2013

	On Sun, Feb 10, 2013 at 06:51:23PM +0000, Anton Shterenlikht wrote:
	> 	Date: Sun, 10 Feb 2013 08:44:24 -0800
	> 	From: Steve Kargl <sgk_at_troutmask.apl.washington.edu>
	> 	To: Boris Samorodov <bsam_at_passap.ru>
	> 	Subject: Re: 7+ days of dogfood
	> 
	> 	> >   FFLAGS = -O2 -pipe -march=native -mtune=native
	> 	> 
	> 	> I don't like using "=" for FLAGS at make.conf...
	> 	> 
	> 	> >   FFLAGS+= -funroll-loops -ftree-vectorize
	> 	> 
	> 	> ... as well as defaults overriding.
	> 	> 
	> 
	> 	FFLAGS are the options used while compiling Fortran.  Having
	> 	spent years contributing to and testing gfortran, I am fairly
	> 	comfortable with these options.
	> 
	> Do you recommend these FFLAGS settings to all
	> users of gfortran (via lang/gcc4x)?
	> 

	Yes.

And for all arches? I use ia64, sparc64 and amd64.

	> For example, I use blas, lapack, slatec, atlas, etc.
	> Should I use these FFLAGS too?

	Without knowing what options you currently use, I cannot
	make a concrete recommendation other than I've extensive
	tested the above options with my own codes and the
	Polyhedron testsuite.  Oh, I do recommend that one should
	avoid -ffast-math (unless one really understands what it
	actually does).

Many thanks

Anton