[PATCH] D104285: [analyzer][AST] Retrieve value by direct index from list initialization of constant array declaration.

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman added a comment.

One thing I think is worth asking in this thread is whether what you're analyzing is undefined behavior?

Array subscripting is defined in terms of pointer addition per: http://eel.is/c++draft/expr.sub#1
Pointer addition has a special behavior for arrays: http://eel.is/c++draft/expr.add#4 ("Otherwise, if P points to an array element i of an array object x with n elements ... Otherwise, the behavior is undefined.")

I am pretty sure that at least in C++, treating a multidimensional array as a single dimensional array is UB because of the strength of the type system around arrays. And when you turn some of these examples into constant expressions, we reject them based on the bounds. e.g., https://godbolt.org/z/nYPcY14a8


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https://reviews.llvm.org/D104285