An inliner should, by itself, never introduce a bug, except maybe inefficient code. An inliner together with other optimizations can definitely lead to weird b

An inliner should, by itself, never introduce a bug, except maybe inefficient code. An inliner together with other optimizations can definitely lead to weird behaviour if you are not intimately familiar with the C spec. Inlining can be a problem as it is the reason many other optimizations are being run. For example, I managed to recover "sensitive data" due to a DSR pass being run after inlining. The code worked fine at O1, but kept "sensitive data" ( not really, it was a programming course in HS where we broke eachothers programs) in memory at O2. Edit: but yes, almost all of the time the problem is PEBKAC.