Nvptx GPU offloading using OpenMP4 and GCC 7.2

[Alexander Monakov]

Hi,

It seems your system has Binutils from before when LTO plugins were supported:

> GNU assembler version 2.20.51.0.2 (x86_64-redhat-linux) using BFD version version 2.20.51.0.2-5.47.el6_9.1 20100205

and so GCC uses a fallback path where collect2 does not pass -plugin options to
system ld, but rather tries to scan input objects itself. Perhaps this fallback
is not working well (sorry, cannot check that right now).  In any case it looks
not widely tested, I believe developers usually have newer binutils.

I think the path of least resistance for you is to also build and install a
recent Binutils tree and rebuild "host" gcc.  Use --enable-plugins and
--prefix=... on the configure command line. Verify that "host"
gcc can find the new ld and enables LTO plugin at configure time.

(or if some module provides new binutils, it's of course simpler to use that)

Also you'll need to remove the '--disable-multilib' configure option from
"nvptx GCC" step (but adding it to the "host GCC" configuration is fine).

Hope that helps.
Alexander