[llvm] r280412 - GlobalISel: add a G_PHI instruction to give phis a type.

[Tim Northover via llvm-commits]

> Which I think I'm OK with really, unless we can come up with a name that really does fit all three cases. I'm working on eliminating some uses of generic regs size at the moment, but after that I'll switch buildCopy to use a new G_COPY.

Of course, an alternative is to put the entire type information into a MachineRegisterInfo side table instead of on each MachineInstr. Then we could keep COPY, PHI, IMPLICIT_DEF and so on for everything. You need an MRI anyway to look up a register's type.

Tim.