advice on gfortran options for a port

[Tijl Coosemans]

On Mon, 27 Jul 2015 10:53:44 +0100 (BST) Anton Shterenlikht <mexas at bris.ac.uk> wrote:
> I'm making a port of http://netlib.org/math/
> 
> The supplied makefile has:
> 
> # This makefile uses features of GNU Make.  Uses bash on Linux.
> # Meant to be run from the directory containing the math77 Fortran directory.
> # You may need to change the first line above, and the definitions of FC,
> # std_flags, and FFLAGS below.  If code is to be used in production,
> # you will want to change the optimization level.  (For example change
> # -ggdb to -O3 or -O2.
> 
> FC = /usr/bin/gfortran
> std_flags=-march=native -fimplicit-none -fno-f2c -fno-backslash\
>  -funroll-loops  -ffpe-trap=zero,overflow,invalid -finit-real=NAN\
>  -ftree-vectorize -floop-interchange -floop-strip-mine -floop-block -pipe
> 
> FFLAGS = -ggdb $(std_flags) -Wall
> 
> Trying to build (with gfortran48 to gfortran6) I get:
> 
> f951: sorry, unimplemented: Graphite loop optimizations cannot be used (ISL is not available)(-fgraphite, -fgraphite-identity, -floop-block, -floop-interchange, -floop-strip-mine, -floop-parallelize-all, -floop-unroll-and-jam, and -ftree-loop-linear)
> 
> Are these not implemented on BSD?
> I wonder how they build with GCC with these flags?
> 
> Anyway, should I leave all these flags, and -ggdb in the port?
> Or should I use the default ports tree FFLAGS instead?

It seems that gcc needs to be configured with --with-isl to enable
Graphite.  Gerald, can this be enabled in the gcc ports?