[PATCH 4/9] [SFN] introduce statement frontier notes, still disabled

[Jason Merrill]

On Sat, Sep 30, 2017 at 5:08 AM, Alexandre Oliva <aoliva@redhat.com> wrote:
> diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
> index a89ee49..f9209ac 100644
> --- a/gcc/cp/constexpr.c
> +++ b/gcc/cp/constexpr.c
> @@ -306,6 +306,9 @@ build_data_member_initialization (tree t, vec<constructor_elt, va_gc> **vec)
>        tree_stmt_iterator i;
>        for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
>         {
> +         if (TREE_CODE (tsi_stmt (i)) == DEBUG_BEGIN_STMT)
> +           /* ??? Can we retain this information somehow?  */

There's no need; the result of this function isn't used for codegen
any more, just checking.

Why do you need a special case for this?  The existing code should
have the same effect.

> @@ -586,6 +590,9 @@ build_constexpr_constructor_member_initializers (tree type, tree body)
>        tree_stmt_iterator i;
>        for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i))
>         {
> +         if (TREE_CODE (tsi_stmt (i)) == DEBUG_BEGIN_STMT)
> +           /* ??? Can we retain this information somehow?  */

Likewise.

> @@ -3783,6 +3791,8 @@ cxx_eval_statement_list (const constexpr_ctx *ctx, tree t,
>    for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
>      {
>        tree stmt = tsi_stmt (i);
> +      if (TREE_CODE (stmt) == DEBUG_BEGIN_STMT)
> +       continue;

Maybe instead of handling this here, add it to the sequence of codes
that are returned unchanged in cxx_eval_constant_expression, after
PREDICT_EXPR?

Jason