RFR: 8325467: Support methods with many arguments in C2

[Vladimir Kozlov]

On Thu, 8 Aug 2024 19:38:41 GMT, Dean Long <dlong at openjdk.org> wrote:

> > Do you know why we use int in OptoReg but short in OptoRegPair? I don't see why we should not change it to short in OptoReg as well for consistency.
> 
> I don't know the reason for the inconsistency. I agree they should use the same type. I suggest using OptoReg::Name in OptoRegPair, and changing its type to short, along with checks that we don't overflow the smaller type.

Platform specific code use `int`. Converting `OptoReg::Name` may need more changes then you think.  I agree with changing `OptoReg::Name` type to `short` but it should be separate from this RFE.
`short` in `OptoRegPair` is for memory saving. In a lot of places (all?) we use `copy value` for it.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/20404#issuecomment-2277062569