Hi folks!

In implementing prange (pointer ranges), I have found a 1.74% slowdown
in VRP, even without any code path actually using the code.  I have
tracked this down to irange::get_bitmask() being compiled differently
with and without the bare bones patch.  With the patch,
irange::get_bitmask() has a lot of code inlined into it, particularly
get_bitmask_from_range() and consequently the wide_int_storage code.

I don't know whether this is expected behavior, and if it is, how to
mitigate it.  I have tried declaring get_bitmask_from_range() inline,
but that didn't help.  OTOH, using __attribute__((always_inline))
helps a bit, but not entirely.  What does help is inlining
irange::get_bitmask() entirely, but that seems like a big hammer.

The overall slowdown in compilation is 0.26%, because VRP is a
relatively fast pass, but a measurable pass slowdown is something we'd
like to avoid.

What's the recommended approach here?

For the curious, I am attaching before and after copies of
value-range.s.  I am also attaching the two patches needed to
reproduce the problem on mainline.  The first patch is merely setup.
It is the second patch that exhibits the problem.  Notice there are no
uses of prange yet.

Thanks.
Aldy