APFloat: x - NaN needs to flip the signbit of NaN when x is a number.

Because we don't have a separate negate( ) function, 0 - NaN does double-duty as the IEEE-754 negate( ) operation, which (unlike most FP ops) *does* attach semantic meaning to the signbit of NaN.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210428 91177308-0d34-0410-b5e6-96231b3b80d8
Fix some more moving-from-moved-from objects issues in SmallVector

(& because it makes it easier to test, this also improves
correctness/performance slightly by moving the last element in an insert
operation, rather than copying it)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210429 91177308-0d34-0410-b5e6-96231b3b80d8
SmallVectorTest: Remove some more robust checks added in r210429 since they caught some bugs I haven't fixed yet.

Specifically this caused inserting an element from a SmallVector into
itself when such an insertion would cause a reallocation. We have code
to handle this for non-reallocating cases, but it's not robust against
reallocation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210430 91177308-0d34-0410-b5e6-96231b3b80d8