[Mesa-dev] [PATCH] Revert "configure.ac: Disable compiler optimizations when --enable-debug is set"
brianp at vmware.com
Tue Jan 8 09:31:33 PST 2013
On 01/08/2013 08:38 AM, Marek Olšák wrote:
> This reverts commit 122345876479cf5cf553e38162ab105658614ab7.
> Some distributions use --enable-debug for testing packages and the commit
> results in terrible CPU performance. It can be embarrassing for us.
Surely people should understand that enabling debugging code/flags can
adversely effect performance.
> Those who do not want optimizations should set the CFLAGS and CXXFLAGS
> environment variables. In my opinion, --enable-debug should only set -DDEBUG.
Previously, if we set --enable-debug we got -g -O2 which was pretty
much useless if you planned to use gdb (and why else would you use
--enable-debug?). That's why I advocated -g -O0.
Just setting -DDEBUG can lead to reduced performance too (in Mesa or
in any other project). For example in the past I've done stuff like:
do extra validation, error checking etc.
which could significantly impact performance, regardless of -g or -O.
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