On Thu, 10 Sep 2026, Tobias Burnus wrote:
> Richard Biener wrote:
> > On Wed, 9 Sep 2026, Tobias Burnus wrote:
> >
> >> This failed as no varpool_node was available when needed and,
> >> as for some reason, the same decl appeared multiple times
> >> in the FOR_EACH_VARIABLE loop. - For some reasons, and possibly
> >> related to VALUE_EXPR, IPA also decided that it could remove that
> >> node - even though it was used. (It worked at -O0)
> > Well, because you add variables by creating a varpool node
> > while looping over the symtab? I don't think this is safe.
> > May I suggest to create a worklist for the varpool creation part?
> >
> > Otherwise, well, I suppose it makes sense.
>
> I concur that it makes sense not to modify the varpool while
> walking it. However, the same DECL still occurs multiple times.
>
> With the following incremental patch (diff -w), I still get for
> libgomp.c/usm_env_handling-1-self.c:
>
> lto1: warning: »A«, 0x7f39b6efc100, 0x7f39b6f02000
> lto1: warning: »A«, 0x7f39b6efc100, 0x7f39b6f02000
> lto1: warning: »A« (»(*A$linkptr)«), 0x7f39b6efc100, 0x7f39b6f02000
But that means we have multiple varpool nodes for the same decl.
Can you varpool->debug () them?
>
> That is: The same node appears multiple times in FOR_EACH_VARIABLE,
> such that the 'if' condition is still required.
>
> Thus, I intent to commit the attached (incremental) patch.
> (Same as the diff below, except for re-indenting and without warning
> calls.)
>
> (diff -w with debug 'warning' calls:)
> --- a/gcc/lto/lto.cc
> +++ b/gcc/lto/lto.cc
> @@ -482,13 +482,23 @@ static void
> offload_handle_link_vars (void)
> {
> #ifdef ACCEL_COMPILER
> + size_t i;
> varpool_node *var;
> + auto_vec <varpool_node *>temp_link_vars;
> FOR_EACH_VARIABLE (var)
> if (lookup_attribute ("omp declare target link",
> DECL_ATTRIBUTES (var->decl)))
> +{
> + temp_link_vars.safe_push (var);
> +warning(0, "%qD, %p, %p", var->decl, (void*) var, (void *) var->decl);
> +}
> + FOR_EACH_VEC_ELT (temp_link_vars, i, var)
> {
> + /* For some reasons, the same varpool node can appear multiple times.
> */
> if (DECL_HAS_VALUE_EXPR_P (var->decl))
> + {
> + warning(0, "%qD (%qE), %p, %p", var->decl, DECL_VALUE_EXPR
> (var->decl), (void*) var, (void *) var->decl);
> continue;
> + }
> tree type = build_pointer_type (TREE_TYPE (var->decl));
> tree link_ptr_var = build_decl (UNKNOWN_LOCATION, VAR_DECL,
> clone_function_name (var->decl,
>
>
> Tobias
>
>
--
Richard Biener <[email protected]>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Jochen Jaser, Andrew McDonald, Abhinav Puri; (HRB 36809, AG Nuernberg)
