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

H. Peter Anvin
2015-04-10T13:19:28Z

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."

As far as the 16-byte alignment, my understanding is not that it is
related to the I$ but rather is the decoder datum.

-hpa