[PATCH] D25482: [PPC] Allow two post RA schedulers to be in the pipeline and select one depending on the Machine Function's subtarget

[Eric Christopher via llvm-commits]

echristo added inline comments.


================
Comment at: lib/CodeGen/MachineFunctionPass.cpp:94-98
+bool MachineFunctionPass::skipFunction(const MachineFunction &MF) const {
+  if (!MF.getSubtarget().runPass(this->getPassID()))
+    return true;
+
+  return FunctionPass::skipFunction(*MF.getFunction());
----------------
amehsan wrote:
> echristo wrote:
> > amehsan wrote:
> > > echristo wrote:
> > > > I'm not sure why you need all of this and can't write the skipFunction without needing a MachineFunction in specific. Can you explain for me?
> > > Because I need MachineFunction's subtarget. Does that answer your question?
> > Not really, but I'd missed any resolution (which didn't appear to happen) for the basic idea of passing in a function to the pass.
> > 
> > Can this be done similar to IfConversion instead? I'd really prefer not to have this overloading of the idea of skipFunction.
> I don't really understand what you mean by "the basic idea of passing in a function to the pass". Could you clarify?
> 
> By IfConversion I believe you are referring to D8717. Could you explain why you prefer that to overloading skipFunction? 
So D8717 allows targets to configure passes by passing in a callback at configuration time. skipFunction is a pretty terrible hack that originally existed as a mechanism to deal with optnone and has an ok side effect of being able to use it for bisection. It's not a use case that should be promulgated further, especially given that the configuration via call back is both easier to understand and just as configurable (and more localized).


https://reviews.llvm.org/D25482