[PATCH] Disable passes on optnone functions

[Nick Lewycky]

Robinson, Paul wrote:
> This patch disables a number of Machine Function Passes for functions
> with the 'optnone' attribute.
>
> To come up with the list of passes, I looked at CodeGen/Passes.cpp,
> and disabled whatever would be excluded under CodeGenOpt::None.
> Except, I did not disable anything listed in addOptimizedRegAlloc(),
> as I can't see how to substitute one RA pass sequence for another on
> a per-function basis.  Maybe there's a way to deal with that safely,
> but for now it seemed prudent (and not horribly harmful to the goals
> of 'optnone') to leave well enough alone.
> If anybody has an idea, we're open to it.

I note that I'm on the 'to' line, but I am certainly not the right 
person to review this. I know some high-level design of the codegen 
parts, but that's about it.

Would someone else please take a look?

Nick