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Re: GCC Release Status (2003-08-22)

On Fri, 29 Aug 2003, Mark Mitchell wrote:

> I don't think we'll have any trouble getting to a release on the C++
> front.
> Compile times are another major story.  I'm not sure what the full
> situation is at this point, and I'm not sure we even know what
> apples-to-apples means.

I'm afraid there are some memory consumption regression presented in
gcc3.4, i.e. on my machine (.5GB RAM + .5GB swap) it compiles some MICO
files and cosumes about 300MB memory where gcc3.2.3/3.3.1 consumes only
about 50-70MB. I'm talking here about C++ compiled with -O0. On the other
hand, there is one file which 3.4 is not able to compile with -O1/-O2,
since it is not able to find free fp register (IIRC).

Yes, I know, I should report both issues, but I guess few MBs of
preprocessed files are useless for you and on the other hand I've not been
able yet to find smaller examples for issues duplication. :-(

> For example, should we assume people will be
> using PCH?

I'm not sure, since to use gcc's pch, the user will need to do:

1) some source code changes to gain maximal speed
2) some build framework changes to add support for manual pch processing

Speaking again for MICO project, I have already done 1. point, since I'm
using Comeau C++ for MICO development (reason: speed with PCH on). On the
other hand I'm not sure if it's worth the effort to do 2. point just for
gcc3.4, especially when gcc compile server seems to be on the good way to
support some kind of automatic processing... but well, maybe I will do it
at the end, since Comeau doesn't provide mt-safe run-time...

BTW: During experiments with gcc's 3.4 PCH, I've been able to compile
MICO's ORB core directory in about 4 minutes - gcc2.95.4 compiles in
about 6 minutes and gcc3.2.3 compiles the same in about 12 minutes. Comeau
with PCH on is about 4-5 minutes.


Karel Gardas        
ObjectSecurity Ltd. 

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