This can be beneficial if there is a fast ABS (For example with X86
vpabs) or if there is a dominating ABS(A) in the DAG.
Note C is constant so ABS(C) is just a constant.
Alive2 Links:
EQ: https://alive2.llvm.org/ce/z/829F-c
NE: https://alive2.llvm.org/ce/z/tsS8bU