[Bug middle-end/113904] [OpenMP][5.0][5.1] Dynamic context selector 'user={condition(expr)}' not handled

["sandra at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113904

--- Comment #5 from sandra at gcc dot gnu.org ---
Per TR12, these are the rules for the scoping/evaluation of these expressions:

"For the match clause of a declare variant directive, any argument of the base
function that is referenced in an expression that appears in the context
selector is treated as a reference to the expression that is passed into that
argument at the call to the base function. Otherwise, a variable or procedure
reference in an expression that appears in a context selector is a reference to
the variable or procedure of that name that is visible at the location of the
directive on which the context selector appears."

C: "Any expressions in the match clause are interpreted as if they appeared in
the scope of arguments of the base function."

C++: "any expressions in the match clause are interpreted as if they appeared
at the scope of the trailing return type of the base function."

Plus, confusingly, it also says:

"All variables referenced by these expressions are considered to be referenced
at the call site."

"All variables that are referenced in an expression that appears in the context
selector of a match clause must be accessible at each call site to the base
function according to the base language rules."

So maybe the intent is that the variables be parsed in the scope of the
directive but then the expressions be inserted inline at the call site, rather
than wrapping them with an internal function?  :-S