On 05/26/2017 01:55 PM, Richard Biener wrote: > On Fri, May 26, 2017 at 1:51 PM, Jakub Jelinek wrote: >> On Fri, May 26, 2017 at 01:46:47PM +0200, Richard Biener wrote: >>> On Thu, May 25, 2017 at 11:23 AM, Martin Liška wrote: >>>> Hello. >>>> >>>> After a discussion with Richi, using adding "-O2" to STAGE1 cflags with a recent >>>> enough compiler can significantly speed up bootstrap. Thus I'm suggesting to >>>> introduce --with-stage1-cflags where one can provide such options. >>> >>> I don't think this is necessary -- you can always override with STAGE1_CFLAGS. >>> >>>> Apart from that, maybe it would be handy to automatically enable "-O2" when >>>> one has a recent compiler? Do we have an example where we detect host compiler >>>> and it's version? >>> >>> Don't know about version but configury already detects that we use GCC, so that >>> knowledge should be readily available. >> >> Well, it certainly shouldn't be -O2 by default for any system GCC, more >> something like if it is major of the configured configure minus 1 or newer >> (or minus 2?), then use -O2, otherwise default to -O0 as before. > > I'd still default to -O0 on release branches regardless of version and then > for development we can probably simply use "any GCC" when people have > the chance to override. Ok, sending new patch that does that on experimental branches for ${CC} --version being a GCC newer than 4.9. Martin > > At least for me host GCC 4.8 works quite well with -O2. > > Richard. > >> Jakub