Add some API to `APSInt` to make it easier to compare with `int64_t`.
- `APSInt::compareValues(APSInt, APSInt)` returns 1, -1 or 0 for
greater, lesser, or equal, doing the right thing for mismatched
"has-sign" and bitwidths. This is just like `isSameValue()` (and is
now the implementation of it).
- `APSInt::get(int64_t)` gets a signed `APSInt`.
- `operator<(int64_t)`, etc., are implemented trivially via `get()`
and `compareValues()`.
- Also added `APSInt::getUnsigned(uint64_t)` to make it easier to test
`compareValues()`.
llvm-svn: 228239
The interaction between defaulted operators and move elision isn't
totally obvious, add a unit test so it doesn't break unintentionally.
llvm-svn: 202662
