Re: [Patch,v3] omp-offload.cc: Fix value-expr handling of 'declare target link' vars [PR115637] (was: [Patch] gimplify.cc: Handle VALUE_EXPR of MEM_REF's ADDR_EXPR argument [PR115637])

[Richard Biener]

On Wed, Jul 31, 2024 at 1:21 PM Tobias Burnus <tbur...@baylibre.com> wrote:
>
> Hi Richard, hi all,
>
> Richard Biener wrote:
>
> Looking at pass_omp_target_link::execute I wonder iff find_link_var_op
> shouldn't simply do the substitution?  Aka
>
> This seems to work ...
>
> --- a/gcc/omp-offload.cc
> +++ b/gcc/omp-offload.cc
> @@ -2893,6 +2893,7 @@ find_link_var_op (tree *tp, int *walk_subtrees, void *)
>        && is_global_var (t)
>        && lookup_attribute ("omp declare target link", DECL_ATTRIBUTES (t)))
>      {
> +      *tp = unshare_expr (DECL_VALUE_EXPR (t));
>        *walk_subtrees = 0;
>        return t;
>      }
>
> which then makes the stmt obviously not gimple?
>
> ... except that 'return t' prevents updating other value-expr in the same 
> stmt, but that can be fixed.
>
> Updated patch attached.

You can pass a

  walk_stmt_info wi;
  wi->data = NULL;

to walk_gimple_stmt and set wi->data instead of using a global
variable (or make wi->data point
to a local variable for some more indirection).

OK as-is or with cleanup as suggested above.

Thanks,
Richard.

> Thanks for the suggestion!
>
> Tobias