Thumb2 code size improvements

[Richard Earnshaw]

On Tue, 2010-09-07 at 13:09 +0100, Andrew Stubbs wrote:
> On 07/09/10 13:01, Yao Qi wrote:
> >> * Investigate reduced alignment constraints?
> >
> > Any details on this?
> 
> No, I just know that some targets like to align functions to 
> cache-lines. This is a useful speed optimization, but does lead to lots 
> of "blank" gaps in the code. I have no real idea if ARM does this kind 
> of thing, or if the ABI has anything to say about it.
> 
> I just suggest that we should check it out - or at least ask an ARM 
> expert if I'm talking nonsense. :)

I'm pretty certain we don't do this with gratuitously -Os on ARM.  We
may, however, align some thumb functions to a 32-bit boundary
unnecessarily (still needed if there's a literal pool).

R.