On Fri, Sep 21, 2018 at 11:04 AM, Marek Polacek <pola...@redhat.com> wrote:
> On Fri, Sep 21, 2018 at 09:37:53AM +0200, Jakub Jelinek wrote:
>> On Thu, Sep 20, 2018 at 11:56:37PM -0400, Marek Polacek wrote:
>> > The patch for P0595R1 - is_constant_evaluated had this hunk:
>> >
>> > @@ -5279,7 +5315,9 @@ maybe_constant_init_1 (tree t, tree decl, bool
>> > allow_non_constant)
>> > else if (CONSTANT_CLASS_P (t) && allow_non_constant)
>> > /* No evaluation needed. */;
>> > else
>> > - t = cxx_eval_outermost_constant_expr (t, allow_non_constant, false,
>> > decl);
>> > + t = cxx_eval_outermost_constant_expr (t, allow_non_constant,
>> > + !allow_non_constant,
>> > + pretend_const_required, decl);
>> > if (TREE_CODE (t) == TARGET_EXPR)
>> > {
>> > tree init = TARGET_EXPR_INITIAL (t);
>> >
>> > the false -> !allow_non_constant change means that when calling
>> > cxx_constant_init strict will be true because cxx_constant_init does not
>> > allow
>> > non constants. That means that for VAR_DECLs such as __func__ we'll call
>> > decl_really_constant_value instead of decl_constant_value. But only the
>> > latter
>> > can evaluate __func__ to "foo()".
>> >
>> > Jakub, was there a specific reason for this change? Changing it back still
>> > regtests cleanly and the attached test compiles again.
>>
>> It just didn't feel right that cxx_constant_init which looks like a function
>> that requires strict conformance still passes false as strict.
>> If there is a reason to pass false, I think we need a comment that explains
>> it.
>
> I think we use strict = true for *_constant_value, but *_constant_init should
> get strict = false.
Right. In _init we try to get constant values for more than just C++
constant expressions.
Jason
