mustBe was barely over budget, so manually inlining the first flag.kind
call is enough. Add a TODO to reverse that in the future, once the
compiler gets better.
mustBeExported and mustBeAssignable were over budget by a larger amount,
so add slow path functions instead. This is the same strategy used in
the sync package for common methods like Once.Do, for example.
Lots of exported reflect.Value methods call these assert-like unexported
methods, so avoiding the function call overhead in the common case does
shave off a percent from most exported APIs.
Finally, add the methods to TestIntendedInlining.
While at it, replace a couple of uses of the 0 Kind with its descriptive
name, Invalid.
name old time/op new time/op delta
Call-8 68.0ns ± 1% 66.8ns ± 1% -1.81% (p=0.000 n=10+9)
PtrTo-8 8.00ns ± 2% 7.83ns ± 0% -2.19% (p=0.000 n=10+9)