Re: [PATCH] x86: Align jump targets to 1 byte boundaries

[Markus Trippelsdorf]

On 2015.04.10 at 06:18 -0700, H. Peter Anvin wrote:
> On 04/10/2015 05:50 AM, Denys Vlasenko wrote:
> > 
> > However, I'm an -Os guy. Expect -O2 people to disagree :)
> > 
> 
> The problem with -Os is that the compiler will make *any* tradeoffs to
> save a byte.  It is really designed to squeeze as much code into a
> fixed-size chunk, e.g. a ROM, as possible.
> 
> We have asked for an -Okernel mode from the gcc folks forever.  It
> basically would mean "-Os except when really dumb."

If you want the best of both worlds perhaps you should reconsider Andy's
LTO patch? With -flto gcc automatically optimizes all functions that it
considers cold for size. So you could expect some code size savings even
with -O2 (or -O3).

-- 
Markus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/