graphics: implement RDNA2 buffer atomic OR x2

src/graphics/shader/recompiler/frontend/decode/MemoryOps.cpp

@@ -58,6 +58,7 @@ constexpr MemoryOpcodeInfo MUBUF_OPCODE_LIST[] = {
     {0x3bu, Opcode::BUFFER_ATOMIC_XOR, 1, 32},
     {0x3fu, Opcode::BUFFER_ATOMIC_FMIN, 1, 32},
     {0x40u, Opcode::BUFFER_ATOMIC_FMAX, 1, 32},
+    {0x5au, Opcode::BUFFER_ATOMIC_OR_X2, 2, 32},
 };
 
 constexpr MemoryOpcodeInfo MTBUF_OPCODE_LIST[] = {

src/graphics/shader/recompiler/frontend/decode/ShaderDecoder.cpp

@@ -600,6 +600,7 @@ std::string InstructionToString(const Instruction& inst) {
 		case Opcode::BUFFER_ATOMIC_UMAX:
 		case Opcode::BUFFER_ATOMIC_AND:
 		case Opcode::BUFFER_ATOMIC_OR:
+		case Opcode::BUFFER_ATOMIC_OR_X2:
 		case Opcode::BUFFER_ATOMIC_XOR:
 		case Opcode::BUFFER_ATOMIC_FMIN:
 		case Opcode::BUFFER_ATOMIC_FMAX:

src/graphics/shader/recompiler/frontend/decode/ShaderDecoder.h

@@ -463,6 +463,7 @@ enum class Opcode {
 	BUFFER_ATOMIC_UMAX,
 	BUFFER_ATOMIC_AND,
 	BUFFER_ATOMIC_OR,
+	BUFFER_ATOMIC_OR_X2,
 	BUFFER_ATOMIC_XOR,
 	BUFFER_ATOMIC_FMIN,
 	BUFFER_ATOMIC_FMAX,