On Thu, Mar 10, 2016 at 12:56 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> On Thu, Mar 10, 2016 at 06:37:32PM +0100, Jakub Jelinek wrote:
>> On Thu, Mar 10, 2016 at 12:34:40PM -0500, Patrick Palka wrote:
>> > Doesn't this mean that we call initializer_constant_valid_p at each
>> > iteration? This would slow down the non-constant case even further.
>> > So I wonder if the return value of initializer_constant_valid_p could
>> > be cached or something, since it seems like a potentially expensive
>> > predicate.
>>
>> You're right, but I've already committed the patch. I'll write an
>> incremental patch and test it.
>
> So, like this?
>
> 2016-03-10 Jakub Jelinek <ja...@redhat.com>
>
> PR c++/70001
> * constexpr.c (cxx_eval_vec_init_1): For pre_init, only
> call initializer_constant_valid_p on the first iteration.
>
> --- gcc/cp/constexpr.c.jj 2016-03-10 12:52:04.000000000 +0100
> +++ gcc/cp/constexpr.c 2016-03-10 18:45:13.416533853 +0100
> @@ -2391,17 +2391,21 @@ cxx_eval_vec_init_1 (const constexpr_ctx
> /* Initializing an element using value or default initialization
> we just pre-built above. */
> if (pre_init_elt == NULL_TREE)
> - pre_init_elt
> - = cxx_eval_constant_expression (&new_ctx, init, lval,
> - non_constant_p, overflow_p);
> - eltinit = pre_init_elt;
> - /* Don't reuse the result of cxx_eval_constant_expression
> - call if it isn't a constant initializer or if it requires
> - relocations. */
> - if (initializer_constant_valid_p (pre_init_elt,
> - TREE_TYPE (pre_init_elt))
> - != null_pointer_node)
> - pre_init_elt = NULL_TREE;
> + {
> + eltinit
> + = cxx_eval_constant_expression (&new_ctx, init, lval,
> + non_constant_p, overflow_p);
> + /* Don't reuse the result of cxx_eval_constant_expression
> + call if it isn't a constant initializer or if it requires
> + relocations. */
> + if (i == 0
> + && (initializer_constant_valid_p (eltinit,
> + TREE_TYPE (eltinit))
> + == null_pointer_node))
> + pre_init_elt = eltinit;
> + }
> + else
> + eltinit = pre_init_elt;
> }
> else
> {
Looks fine to me :)
