openrisc_sim.c:87:42: error: 'cpu_irqs[0]' may be used uninitialized in this function [-Werror=maybe-uninitialized]

I see the warning since gcc10:

static void openrisc_sim_init(MachineState *machine):
...
    qemu_irq *cpu_irqs[2];
...


    serial_mm_init(get_system_memory(), 0x90000000, 0, serial_irq,
                   115200, serial_hd(0), DEVICE_NATIVE_ENDIAN);

I would initialize cpu_irqs[2] with {}.