It looks like your patch fixes the issue.

My tests passed without issues, and the compilation succeeded.

the clang job took longer than 1500 seconds and was cut by the default ctest timeout of 1500 seconds. the tests in release mode on clang took 1347 seconds on my raspberry pi 4. so already without emulation, close to not making the limit.

@lemire I think the actual fix is noncontroversial and could be merged, but the changes with SIMDUTF_FAST_TESTS needs review.

@pauldreik

I am puzzled as to why tests should be running too long now? Didn't they work in the past ?

In any case, PR #876 looks promising.

I can review whenever you want. I reviewed your code change and it is good, verified.

Do you want to split the work in two PRs ?

I am also puzzled why it would fail now. Maybe there was larger pressure on github than usual?
No, I can't remember seeing CI timeouts before.

I will split this in two PR-s since they are two different problems and it is more easy to see afterwards what has changed.

Merging this bug fix first, then let's keep going in the other PR!