Oddity with `-Wpass-failed=loop-spawning`

[wheatman]

Compiling some code gave the warning

warning: Tapir loop not transformed: failed to use divide-and-conquer loop spawning.  Compile with -Rpass-analysis=loop-spawning for more details. [-Wpass-failed=loop-spawning]

However, this warning seems unknown and trying to add it to any compilation gives a

warning: unknown warning option '-Wpass-failed=loop-spawning'; did you mean '-Wpass-failed'? [-Wunknown-warning-option]

Also the warning was only appearing for this particular codebase if I compiled it with sanitizers -fsan itize=cilk,undefined,address

If you cannot reconstruct what is going on let me know and I can try to get a minimal example. I was having trouble making any sort of small example since I am not sure what is triggering the warning initially.