[llvm] [AMDGPU] Insert readfirstlane for uniform VGPR arguments (PR #178198)

[Harald van Dijk via llvm-commits]

hvdijk wrote:

I'm seeing
```console
/home/harald/source/llvm-project/llvm/lib/Target/M68k/GISel/M68kCallLowering.cpp:151:6: error: no declaration matches ‘void llvm::M68kIncomingValueHandler::assignValueToReg(llvm::Register, llvm::Register, const llvm::CCValAssign&)’
  151 | void M68kIncomingValueHandler::assignValueToReg(Register ValVReg,
      |      ^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /home/harald/source/llvm-project/llvm/lib/Target/M68k/GISel/M68kCallLowering.cpp:15:
/home/harald/source/llvm-project/llvm/lib/Target/M68k/GISel/M68kCallLowering.h:55:8: note: candidate is: ‘virtual void llvm::M68kIncomingValueHandler::assignValueToReg(llvm::Register, llvm::Register, const llvm::CCValAssign&, llvm::ISD::ArgFlagsTy)’
   55 |   void assignValueToReg(Register ValVReg, Register PhysReg,
      |        ^~~~~~~~~~~~~~~~
/home/harald/source/llvm-project/llvm/lib/Target/M68k/GISel/M68kCallLowering.h:47:8: note: ‘struct llvm::M68kIncomingValueHandler’ defined here
   47 | struct M68kIncomingValueHandler : public CallLowering::IncomingValueHandler {
      |        ^~~~~~~~~~~~~~~~~~~~~~~~
/home/harald/source/llvm-project/llvm/lib/Target/M68k/GISel/M68kCallLowering.cpp:185:6: error: no declaration matches ‘void {anonymous}::CallReturnHandler::assignValueToReg(llvm::Register, llvm::Register, const llvm::CCValAssign&)’
  185 | void CallReturnHandler::assignValueToReg(Register ValVReg, Register PhysReg,
      |      ^~~~~~~~~~~~~~~~~
/home/harald/source/llvm-project/llvm/lib/Target/M68k/GISel/M68kCallLowering.cpp:41:8: note: candidate is: ‘virtual void {anonymous}::CallReturnHandler::assignValueToReg(llvm::Register, llvm::Register, const llvm::CCValAssign&, llvm::ISD::ArgFlagsTy)’
   41 |   void assignValueToReg(Register ValVReg, Register PhysReg,
      |        ^~~~~~~~~~~~~~~~
/home/harald/source/llvm-project/llvm/lib/Target/M68k/GISel/M68kCallLowering.cpp:35:8: note: ‘struct {anonymous}::CallReturnHandler’ defined here
   35 | struct CallReturnHandler : public M68kIncomingValueHandler {
      |        ^~~~~~~~~~~~~~~~~
/home/harald/source/llvm-project/llvm/lib/Target/M68k/GISel/M68kCallLowering.cpp:41:8: warning: ‘virtual void {anonymous}::CallReturnHandler::assignValueToReg(llvm::Register, llvm::Register, const llvm::CCValAssign&, llvm::ISD::ArgFlagsTy)’ used but never defined
   41 |   void assignValueToReg(Register ValVReg, Register PhysReg,
      |        ^~~~~~~~~~~~~~~~
```
after this, are you able to address this quickly or should we temporarily revert?

https://github.com/llvm/llvm-project/pull/178198