On Friday 18 March 2016 05:43 PM, Arnd Bergmann wrote: > I think it's dangerous to use -O3 in one architecture when nothing else > uses it. If you don't have a strong reason to use -O3, maybe just drop that > use the default -O2 -Wmaybe-uninitialized like everyone else does. I know what u mean. In fact top level makefile change has bitten us atleast once. However ARC gcc tends to generate better code (likely others do too) at -O3 and increased inlining etc reflects in several benchmarks. Maybe its due to the micro-architecture and smaller hardware call return stack - I'm not sure. So I'm ready to pay that maintenance price. And it has been like this for 5+ years and I fear that switching to -O2 might unravel something unwarranted for. OTOH, I'd rather prefer -O3 for all arches but that ain't gonna happen for obvious reasons :-) > On a related note, I have submitted a patch that turns CONFIG_CC_OPTIMIZE_FOR_SIZE > into a choice statement, so we actually get the -Wmaybe-uninitialized warnings > in an allyesconfig or allmodconfig build. It would be trivial to extend that > to give the choice between -Os, -O2 and -O3, and then pick -O3 in a defconfig, > over the -O2 default. Is it posted already. I couldn't find it with quick googling. Thx, -Vineet -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
