On Mon, Apr 21, 2025 at 04:39:55PM -0400, Jason Merrill wrote:
> Tested x86_64-pc-linux-gnu, OK for trunk?
>
> -- 8< --
>
> While working on PR119162 it occurred to me that it would be simpler to
> detect the problem of a value referring to a heap allocation if we stopped
> setting TREE_STATIC on them so they naturally are not considered to have a
> constant address. With that change we no longer need to specifically avoid
> caching a value that refers to a deleted pointer.
>
> But with this change maybe_nonzero_address is not sure whether the variable
> could have address zero. I don't understand why it returns 1 only for
> variables in the current function, rather than all non-symtab decls; an auto
> variable from some other function also won't have address zero. Maybe this
> made more sense when it was in tree_single_nonzero_warnv_p before r7-5868?
>
> But assuming there is some reason for the current behavior, this patch only
> changes the handling of non-symtab decls when folding_cxx_constexpr.
>
> PR c++/119162
>
> gcc/cp/ChangeLog:
>
> * constexpr.cc (find_deleted_heap_var): Remove.
> (cxx_eval_call_expression): Don't call it. Don't set TREE_STATIC on
> heap vars.
> (cxx_eval_outermost_constant_expr): Don't mess with varpool.
>
> gcc/ChangeLog:
>
> * fold-const.cc (maybe_nonzero_address): Return 1 for non-symtab
> vars if folding_cxx_constexpr.
LGTM.
Jakub
