8 Expressions [expr]

8.5 Compound expressions [expr.compound]

8.5.13 Bitwise inclusive OR operator [expr.or]

inclusive-or-expression:
	exclusive-or-expression
	inclusive-or-expression | exclusive-or-expression
The usual arithmetic conversions are performed; the result is the bitwise inclusive OR function of its operands.
The operator applies only to integral or unscoped enumeration operands.