Hi!

This extends -Wint-in-bool-context to uses of enum values in boolean
context, and fixes one place where accidentally an enum value was
passed to a bool parameter.

I excluded enum values 0 and 1 because that is used in
gimple-ssa-strength-reduction.c, where we have enums
which are passed in bool function arguments:

enum stride_status
{
   UNKNOWN_STRIDE = 0,
   KNOWN_STRIDE = 1
};

enum phi_adjust_status
{
   NOT_PHI_ADJUST = 0,
   PHI_ADJUST = 1
};

enum count_phis_status
{
   DONT_COUNT_PHIS = 0,
   COUNT_PHIS = 1
};

I would'nt use an enum in that way, but I think it is
at least not completely wrong to do it like that...


Unfortunately C is less strict with enum values, and from
and enum we only see an integer value without an enum type
in C.

Therefore this warning does not work in C, only in C++.
Also integer constants do not have a source location, so
the displayed location is usually a bit vague.
But I think it is still better than no warning at all.


Bootstrapped and reg-tested on x86_64-pc-linux-gnu.
Is it OK for trunk?


Thanks
Bernd.