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Re: C++ PATCH: Allocate implicit constructors lazily
Gerald Pfeifer wrote:
On Sat, 17 Jul 2004, Mark Mitchell wrote:
This patch causes us to allocate implicit default and copy
constructors lazily, which results in about another 2% memory savings
on the Qt test case I've been analyzing.
Which test is this, exactly? Also, I'd be interested to see results
for PR8361 for this kind of patches. ;-)
The test is the compiation (at -O0 -g) of Qt and one of its example
applications on an OS X machine, using precompiled headers. The
characteristics may be different from PR 8361. In Qt, there is very
little use of templates, and most functions are small. The OS X headers
have some characteristics that are different from other system headers
that could also have an impact.
It would be suprising to me if the changes I've been making would make a
negative impact on programs -- but I would not be amazed if an
optimizing compilation of an expression-template programs was not
improved to the same degree as the Qt compilation.
I'm not planning on measuring PR 8361, but I will of course be
responsive if my patches are causing regressions -- performance or
otherwise.
--
Mark Mitchell
CodeSourcery, LLC
(916) 791-8304
mark@codesourcery.com