On 19/03/12 16:11, Andrew Lowe wrote:
On 03/19/12 17:39, Nikos Chantziaras wrote:
On 19/03/12 07:26, Andrew Lowe wrote:
Hi all,
Has anyone played around with the various "better known" compilers on
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You don't need to "change" compilers. You can use whatever one you like
to build your program. The compiler portage uses to build its packages
does not affect your own usage of the others.
As for the fastest one, I can only speak for Intel CPUs where Intel C++
gives me the fastest binaries.
Nikos,
Your experience with Intel is what I'm after. Aster, the FEA code I'm
going to use is not in Portage hence I will be using it's own build
system. When you've used Intel, have you just exported "CC="icc" or
something similar, as make.conf won't be used? Also, I've read somewhere
that there are libraries that you have to link against that are specific
to the Intel compiler as it does not create libraries that are
comparable with the gcc produced ones - is this true or does the
compiler now "play well" with the gcc world?
No special libs required. The binaries I get (both C and C++) don't use
anything extra. I checked both with "ldd" as well as with lsof at
runtime (in case it dlopens anything).
For building, you use "CC=icc" and "CXX=icpc" for regular makefiles or
autoconf scripts. I mostly use qmake though (I use Qt for my GUIs). In
that case, you call qmake like this:
qmake -spec linux-icc
and it creates a makefile that will use ICC. This is also an example of
ICC using C and C++ libs (Qt is C++) that were built by GCC without
issues; its ABI is fully GCC compatible.
There are way to use ICC for portage too. I tried that once. It worked
quite well. But I didn't went with it since too much of a bother.
Note that the link Florian posted is a bit outdated. For example the
sections that tells you that "binaries compiled with icc won't work
after icc is uninstalled" is not true. They will work just fine. The
exception of course if when you specifically use an ICC library, like
the Intel math kernel library.
