On Mon, Nov 10, 2025 at 03:49:26PM -0600, Segher Boessenkool wrote: > Hi! > > On Mon, Nov 10, 2025 at 11:25:29PM +0530, Surya Kumari Jangala wrote: > > I believe the global variable rs6000_cpu can be used, at least in some > > places in this patch wherever TARGET_FUTURE is being used. In other places > > too, perhaps we can avoid this variable? The main issue is it is not > > clear how will we handle any new processor that may be developed after the > > potential FUTURE processor. > > We should not have a "Future" thing that stands in for any future stuff. > > The thing we _now_ call "Future" we will rename (probably to POWER12, > but who knows!) soon enough. And then when we start doing stuff for > what everyone assumes wil be called POWER13, we'll call that "Future" > again, for the time being. We cannot suggest that POWER13 will have > feature X, and Y execution units, and speed Z. Some people are afraid > that if we (developers) state we have some goal, that customers will see > that as something we promised them, and then maybe even sue us.
This was in the previous set of patches, where I split the ISA flags into the current ISA flags (i.e. ones with a -m option meant for users to enable or disable), and the cpu option bits that were only set via -mcpu=<xxx>. But that is complicated to explain. Note, some of the interfaces, such as the interfaces that define the macros and the stuff for target attribute/pragma do not use the global TARGET_* macros. These interfaces currently are only passed the ISA flags. In my previous patches, I passed the extra CPU option bits. In the current patch, I just pass the extra boolen for future. > There always is just one thing called Future, but it is a stand-in name > for one particular name at all times, it never is nor will be a generic > thing for "whatever shows up in the future". It is a workaround for > big corporation bureaucracy, not a development strategy. > > If we had overlapping generations of development, we'd have a FUTURE2 > as well :-) I have had times in the past where internally I had separate future machines. > We can sugarcoat it a bit in helptexts, but that is about it. Whenever > you see "Future", you can probably guess what the CPU will be called > when (and if!) it eventually shows up. And then when the hardware is > publically announced, we will rename stuff. > > But we never said that Power_(N+1) will have these features, or this > speed, etc. :-) I will recode it to just use ISA bits. I will use Warn(...) to tell the user not to use -mfuture. -- Michael Meissner, IBM PO Box 98, Ayer, Massachusetts, USA, 01432 email: [email protected]
