[dataflow] partial register handling

[Rask Ingemann Lambertsen]

On Thu, May 10, 2007 at 07:43:19PM +0200, Roman Zippel wrote:

> Looking closer at this I don't think strict_low_part should be required
> as splitting DI registers produces a lot of (subreg:SI (reg:DI)) even as
> destination, but they only set strictly part of the register. If I look
> through i386/m68k I don't see a single (strict_low_part (subreg:SI)).

   That's because with UNITS_PER_WORD == 4, (subreg:SI (reg:DI) n) is
implicitly a strict low part for n == 0 or n == 4. When used as destination,
such a subreg is defined as not clobbering anything outside the subreg.

-- 
Rask Ingemann Lambertsen