On 01/15/2015 01:47 PM, Luke Deller wrote: > Hi, > > I saw that gcc-4.8 introduced a new optimization level -Og which enables > optimizations that do not interfere with debugging. > > Yesterday I floated the idea on IRC of using this with --enable-debug > rather than -O0 if available, and some feedback was that it enables gcc > to report extra warnings which would be a good thing.
somebody had the same idea last week... and i've now discovered this old thread... > I tried it out and can see that it does indeed break the build if > --enable-werror is enabled, eg: > > /home/deller/build/libo/vcl/unx/glxtest.cxx: In function ‘void glxtest()’: > /home/deller/build/libo/vcl/unx/glxtest.cxx:236:44: error: ignoring > return value of ‘ssize_t write(int, const void*, size_t)’, declared with > attribute warn_unused_result [-Werror=unused-result] > write(write_end_of_the_pipe, buf, length); > > So I guess this means we couldn't incorporate -Og until all these new > warnings are fixed right? i've fixed all spurious warnings from GCC 6.2.1 -Og on master. > Any other thoughts on whether this is a good idea to pursue? One fear > was that it might slow down compilation, but it doesn't actually seem to > slow down "make clean && make" much at all for me. I'll get some proper > timing measurements. i've done a few timings, see the commit message of https://gerrit.libreoffice.org/#/c/31334/ summary: from-scratch make check is a tiny bit slower (75m -O0, 76m -Og) *but* incremental make check is 20% faster (12m vs. 15m) so for the average developer it should be a win. > (A draft patch is attached to enable -Og if available) thanks, i've taken the configure part of this. only open question is if it actually works as advertised, i.e. is gdb confused by the optimized code or not. anybody want to experiment? _______________________________________________ LibreOffice mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/libreoffice
