On Thu, May 20, 2010 at 08:59:32PM -0700, Mark Mitchell wrote: > David Edelsohn wrote: > > No one disagrees with the potential benefit of the feature. > > OK; I must have misremembered. > > I believe our current implementation keeps track of FP usage through the > front-end, and then disables any floating-point registers by futzing > with fixed_regs and such when compiling each function. There appear to > be no back-end specific patches at all. If that sounds like a > reasonable approach, we might be able to get that into 4.6.
The primary backend specific bit was the addition of a predicate to indicate which registers are FP registers so that they can be marked appropriately. The SH backend changes were more invasive, but not out of the ordinary given what I understand of floating-point and the SH family. Many backends already had such a macro; the only change was exposing that macro via the new target macro. If there's already a way to do this that doesn't involve the addition of a new predicate, that would of course be the better route. -Nathan
