GCC does this too fwiw. Whether or not it is considered a bug, it doesn't have one particular root cause. Several common optimization passes assume small functi

GCC does this too fwiw. Whether or not it is considered a bug, it doesn't have one particular root cause. Several common optimization passes assume small function body. Since functions are typically small, many optimizations use this as a window for heavyweight passes. In other words, intraprocedural optimisation has always been more aggressive than interprocedural optimisation. If you try inlining every function ever into one giant function, you'll be forced to scale back optimization levels.