GCC 12 thinks that `actual` might be used uninitialised. It's not, the use is guarded by `bad_mmcr2` which is only set to true at the same point where `actual` is initialised. cycles_with_mmcr2_test.c: In function ‘cycles_with_mmcr2’: cycles_with_mmcr2_test.c:81:17: error: ‘actual’ may be used uninitialized [-Werror=maybe-uninitialized] 81 | printf("Bad MMCR2 value seen is 0x%lx\n", actual); Silence the warning by initialising `actual` to zero. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220801113746.802046-1-mpe@ellerman.id.au