SHRQ $7, DX, (BX)                       // 480fac1307
	SHRQ $7, R11, (BX)                      // 4c0fac1b07
	SHRQ $7, DX, (R11)                      // 490fac1307
	SHRQ $7, R11, (R11)                     // 4d0fac1b07
	SHRQ $7, DX, DX                         // 480facd207
	SHRQ $7, R11, DX                        // 4c0facda07
	SHRQ $7, DX, R11                        // 490facd307

	v_0 := v.Args[0]
	b := v.Block
	// match: (SHRQ x (MOVQconst [c]))
	// result: (SHRQconst [int8(c&63)] x)
	for {
		x := v_0
		if v_1.Op != OpAMD64MOVQconst {
			break
		}
		c := auxIntToInt64(v_1.AuxInt)
		v.reset(OpAMD64SHRQconst)
		v.AuxInt = int8ToAuxInt(int8(c & 63))
		v.AddArg(x)
		return true
	}
	// match: (SHRQ x (MOVLconst [c]))
	// result: (SHRQconst [int8(c&63)] x)