ArgumentPromotion unpacks recursive types endlessly

[jdoerfert]

Bugzilla Link	42683
Version	trunk
OS	Linux
Attachments	reproducer

Extended Description

ArgumentPromotion checks for "self recursive" functions but not for recursion that involves more than one function. This code was a "fix" for #9304 .

Reproducer is attached.

[jdoerfert]

I will work on ArgPromotion and fix this in the process.

[nikic]

This issue still exists.

[nikic]

Candidate patch: https://reviews.llvm.org/D119418