[PATCH, committed] Function specific option changes (IA-64, hot/cold, scheduling)

[Andrew Pinski]

On Sun, Jul 27, 2008 at 4:55 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> How about a switch to apply a specific set of optimization to all cold
> functions,  like -Os -mpreferred-stack-boundary=2? Of cause, it should
> be off by default.

Why not just better tune the compiler?  Seriously what is happening is
that are marking functions which are not really cold.  I don't see it
is better to turn this off by default or even have a switch.  The
compiler should be smart enough to figure out if a function is cold or
not.  I don't see why we should turn this off by default at all.  I
guess you don't understand what this is good for really.  I think the
issue is what is a cold function and what is a hot function.  A cold
function to me means it will almost never be called or only called
during startup time so the time it takes is no use really compared in
the size savings that I would get.  Most developers don't care if you
supply the compiler with -O2 or -Os, they really want the best
optimizations out of the compiler including code size reduction for
the coldest functions.

What is the definition of a cold function to you?


-- Pinski