Use lambda to forward arguments

This seems to cost 4-5 seconds in build time in the file

Author: arsenm

llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp

@@ -157,11 +157,11 @@ static DecodeStatus decodeRegisterClassImpl(MCInst &Inst, unsigned Imm,
   return addOperand(Inst, DAsm->createRegOperand(RegClassID, Imm));
 }
 
-using RegClassDecoder = decltype(&decodeRegisterClassImpl<0>);
-
 #define DECODE_OPERAND_REG_8(RegClass)                                         \
-  static const constexpr RegClassDecoder Decode##RegClass##RegisterClass =     \
-      decodeRegisterClassImpl<AMDGPU::RegClass##RegClassID>;
+  static const constexpr auto Decode##RegClass##RegisterClass =                \
+      [](auto... args) {                                                       \
+        return decodeRegisterClassImpl<AMDGPU::RegClass##RegClassID>(args...); \
+      };
 
 #define DECODE_SrcOp(Name, EncSize, OpWidth, EncImm)                           \
   static DecodeStatus Name(MCInst &Inst, unsigned Imm, uint64_t /*Addr*/,      \