[SelectionDAG] Teach computeKnownBits about ATOMIC_CMP_SWAP_WITH_SUCCESS boolean return value

The second return value of ATOMIC_CMP_SWAP_WITH_SUCCESS is known to be a
boolean, and should therefore be treated by computeKnownBits just like
the second return values of SMULO / UMULO.

Differential Revision: https://reviews.llvm.org/D42067


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@322985 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed