RE: [Boost-users] long compilation time of variant over long typelist with gcc

From: Ben Hutchings (ben.hutchings_at_[hidden])
Date: 2004-02-11 10:15:56

Graeme Lufkin <gwl_at_[hidden]> wrote:
<snip>
> 	When I compile code that declares a variable of this variant
> type, the compilation takes unreasonably long (like, 1.5 hours on a
> 2Ghz machine).  For fewer types it goes much quicker, the transition
> to unreasonably long happens around 14 types in the mpl::vector.
<snip>
> 	Something else I've noticed: the Intel compiler doesn't have the
> compilation problem!  I've attached sample case code that uses 16
> types, which takes less than 5 seconds to compile with Intel 8.0 and 
> almost 200 with GCC 3.2.2 (both on linux).
> 	When I try the full 20 types I need, GCC chugs for several
> hours, which is unacceptable for my project.  Is there anything I can
> do, or is this a GCC shortcoming that I need to wait for?

I suggest you try newer versions of GCC (3.3 and 3.4 beta); if those
still have the problem then report this as a bug at
<http://gcc.gnu.org/bugs.html> with the keyword "compile-time-hog".

Also check whether the poor performance is due to swapping, which
indicates excessive use of memory and not necessarily excessive use of
CPU time.