[svn ci] :non_volatile

[Jonathan Worthington]

Hi,

Earlier today I checked in a change that lets you add a :non_volatile flag 
to a local or parameter.

.param int i :non_volatile
.local int j :non_volatile

This says to the register allocator "don't re-use the register that this 
parameter or local goes in to", which is rather useful if you are creating a 
reference to the register in question and expecting it not to be re-used for 
something else.

Jonathan