llvm-project

f2e62cfc - [VPlan] Add VPPhi subclass for VPInstruction with PHI opcodes.(NFC) (#139151)

[VPlan] Add VPPhi subclass for VPInstruction with PHI opcodes.(NFC) (#139151) Similarly to VPInstructionWithType and VPIRPhi, add VPPhi as a subclass for VPInstruction. This allows implementing the VPPhiAccessors trait, making available helpers for generic printing of incoming values / blocks and accessors for incoming blocks and values. It will also allow properly verifying def-uses for values used by VPInstructions with PHI opcodes via https://github.com/llvm/llvm-project/pull/124838. PR: https://github.com/llvm/llvm-project/pull/139151