llvm-project

aeaf319b - [flang] avoid useless rebox of polymorphic scalars (#145507)

[flang] avoid useless rebox of polymorphic scalars (#145507) Do not create new descriptor for polymorphic scalars when lowering hlfir.declare. hlfir.declare of box/class is lowered to a fir.rebox to ensure that local lower bounds and descriptor attributes (Pointer/Allocatable/None) are properly set-up in the descriptor associated to the symbol. For polymorphic scalar, this created a useless temporary descriptor. This was breaking invalid code #145256 that violates OPTIONAL usage rules. I am not fixing it primarily to support this invalid code, but rather because it is dumb to create a useless fir.rebox.