On Wed, May 13, 2009 at 09:33:20AM +0200, Andi Kleen wrote: > "Joseph S. Myers" <jos...@codesourcery.com> writes: > > > On Tue, 12 May 2009, Chris Lattner wrote: > > > >> 1. I have a hard time understanding the code size numbers. Does 10% mean > >> that > >> GCC is generating 10% bigger or 10% smaller code than llvm? > > > > I have a different comment on the code size numbers: could we have > > comparisons of code size for -Os rather than (or in addition to) -O2 and > > -O3? If someone is particularly concerned with code size, -Os is what > > they are expected to use. > > It's a slippery slope that -O2 is getting so bad regarding > code size. What should people do who need performance, but cannot > completely disregard code size (and can't use profile feedback for > some reason).
For x86_64/i?86 http://gcc.gnu.org/ml/gcc-patches/2009-05/msg00702.html patch might buy back around 2% for -O2 code (at least it does so for cc1plus binary), and perhaps improving min_insn_size might give further code size improvements at -O2. Jakub
