INTEGRATE_THRESHOLD ever changed?

[Stan Shebs <shebs at apple dot com>]

The macro INTEGRATE_THRESHOLD is defined and documented as a possibly
target-specific heuristic to help decide when to inline functions.
However, I don't see that any target actually uses anything but the
default formula, which is 8 * (8 + num_arguments) instructions.

The reason I ask is that Apple's code has a version that calculates
the actual number of call-used registers at the point where the
compiler is thinking about whether to inline, and multiplies by
that instead of by 8 always.  While this seems clever, I'm wondering
if it's really necessary to go that far.  There are no references to
results of testing or anything like that, so I don't know where and
when this was supposed to be a win.  The fact that no standard GCC
target ever changes the macro suggests that it's not really worth
tinkering with.

Does anybody think this is worth investigating further, or does it
sound like an oddball hack that I should remove from Apple's sources?

Stan