env CC="/usr/bin/clang" CCX="/usr/bin/clang" ./configure > /dev/null ;and make -j 4 > /dev/null

./Modules/timemodule.c:113:13: warning: code will never be executed [-Wunreachable-code]
            PyErr_SetString(PyExc_OverflowError,
            ^~~~~~~~~~~~~~~
1 warning generated.

It does seem like the values CLOCKS_PER_SEC, _PyTime_MAX and SEC_TO_NS are all defined at compile-time, so presumably this can be a compile-time error.

As currently defined, though, it seems very unlikely that this would ever be false, since _PyTime_MAX is the same as LLONG_MAX, which cplusplusreference says is `9223372036854775807 (2**63-1) or greater` [0], so CLOCKS_PER_SEC would need to be >= 2**50, which is unlikely to be... accurate.

In any case, it seems like this check can happen at compile-time, either resulting in compilation failing, or just undefining HAVE_CLOCK.

[0] http://www.cplusplus.com/reference/climits/

Sorry, I should say unlikely that it should ever be *true*. It seems unlikely that there is a platform or piece of hardware on which this error would be raised.

Hi Paul,

Thank you for your explanation, I was not sure about the solution and I have just preferred to publish this issue. I don't have this issue with gcc, only with clang.