Register Allocation

["Adrian Strätling" <adrian.straetling@cs.tu-chemnitz.de>]

Hi,

I'm working on a target that does support up to 8 parallel instructions, 
but they have to be grouped at compile time. The scheduler could do much 
better than it currently does if there were less (output) depencies.

Is it possible to tell the register allocator not to reduce the register 
count to the minimum?

example:
( || means that this insn is executed in parallel to the last one )

1)    mvkl  L4,     b4      \
2)    mvkh  L4,     b4      +   push ret_label
3)    stw   b4,     *--b15  /
   || mvkl  times2, b4      \
4)    mvkh  times2, b4      +   branch
5)    b     b4              /
L4:

If the second temporary were not assigned to b4 but to b5, the schedule 
would be shorter:

1)    mvkl  L4,     b4
   || mvkl  times2, b5
2)    mvkh  L4,     b4
   || mvkh  times2, b5
3)    stw   b4,     *--b15    
   || b     b5
L4:

Thanks,
Adrian