search for: sndpoutflag

...ng the instruction as SDNPInFlag, and specifying a conditioncode parameter. This may require the addition of some kind of condition-code base type to mark conditioncode operands. Alternatively, CPU flags can be modeled using a special flags register (or register class?). In which case, SNDPInFlag/SNDPOutFlag should be killed, and all instructions which modify the flags (even as a side-effect) should do so explicitly. In this case, setcc should always set a special flags register. Just my 2c. Thoughts?

...NPInFlag, and specifying a conditioncode > parameter. This may require the addition of some kind of > condition-code base type to mark conditioncode operands. > > Alternatively, CPU flags can be modeled using a special flags register > (or register class?). In which case, SNDPInFlag/SNDPOutFlag should be > killed, and all instructions which modify the flags (even as a > side-effect) should do so explicitly. In this case, setcc should > always set a special flags register. > > Just my 2c. > Thoughts? > _______________________________________________ > LLVM Developer...

...> That's not it at all. These model instructions reading / writing > MVT::Flag a value. That just mean from the scheduler's point of view > the node that produces a MVT::Flag and the user have to be scheduled > together. Wow. That's just super confusing. So SDNPInFlag/SNDPOutFlag is used only for scheduling? I think you're misunderstanding ISD::SETCC. I may well be misunderstanding setcc, but my misunderstanding is due, at least in part, to the lack of clarity in the model. Also, why are conditional branches modeled in the Initial Selection DAG as a setcc/brcond pair...