Compiler performance tests on FreeBSD 10.0-CURRENT
dimitry at andric.com
Wed Sep 5 09:31:25 UTC 2012
On 2012-09-05 01:40, Garrett Cooper wrote:
> Steve does have a point. Posting the results of
> CFLAGS/CPPFLAGS/LDFLAGS/etc for config.log (and maybe poking through
> the code to figure out what *FLAGS were used elsewhere) is more
> valuable than the data is in its current state (unfortunately..
> autoconf makes things more complicated).
Just to note, autoconf is not used in the FreeBSD source tree, so it
does not apply to the first two builds in the performance test (e.g.
building in-tree clang and gcc).
The other build is Boost, which has yet another totally different build
system, based on Perforce's Jam. Again, no autoconf.
In any case, for all three builds, the default optimization options were
1) For building the FreeBSD in-tree version of clang 3.2:
-O2 -pipe -fno-strict-aliasing
These are just the default FreeBSD optimization flags for building
clang, which are probably used by the majority of users out there.
This is the case that I was interested in particularly. The
-fno-strict-aliasing is not really my choice, but it was introduced
in the past by Nathan Whitehorn, who apparently saw problems without
it. It will hopefully disappear in the future.
2) For building the FreeBSD in-tree version of gcc 4.2.1:
These are the default FreeBSD optimization flags.
3) For building Boost 1.50.0:
-ftemplate-depth-128 -O3 -finline-functions
These are the Boost defaults for gcc-compatible compilers, from
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