Hi!

A bit late to the game...  :-)

On Fri, 6 Apr 2012 18:55:28 -0400, Diego Novillo <dnovillo@google.com> wrote:
> I have started testing the switch to C++ and there is a pile of
> testing to be done.  The testing itself is trivial, but the number of
> targets that need to be tested is large and I don't have access to all
> these combinations.

i686-gnu would be mine.

This is based on 8b64dc3c58b54d07156c99a24576be76e8cbdc10 (2012-05-28)
sources, doing native builds on x86 Debian GNU/Linux as well as x86
Debian GNU/Hurd.

When --enable-build-with-cxx is enabled:

  * Build time mostly stays the same.

  * Looking at the build log, the build system's gcc (as opposed to g++)
    is still being used for building libiberty, fixincludes, zlib,
    libdecnumber, *_FOR_BUILD stuff in gcc/Makefile.  The latter seems to
    have been addressed in a44c8c3b1ee8ae1779fd8ee1ad556ed86a608bd2
    (2012-05-31), the others are probably expected to continue using gcc.

  * The size of the build directory stage1-gcc shrinks (!) from 1.1 GiB
    to 0.4 GiB, such that the whole build tree then occupies 2.6 GiB
    instead of 3.2 GiB.  I did notice that the C build uses
    -fkeep-inline-functions, and the C++ build doesn't (my logs, and
    confirmed in the top-level configure.ac), but don't know if that is
    the (sole) reason; I have not looked at this in more detail -- but
    0.6 GiB or 60 % less is quite a bit.

  * No difference in testsuite results.

When building a i686-linux-gnu to i686-gnu cross-compiler, there are
(expectedly) no surprises either.


Grüße,
 Thomas