On Fri, Jan 17, 2025 at 06:38:45PM -0500, Jason Merrill wrote:
> On 1/17/25 1:31 PM, Marek Polacek wrote:
> > On Fri, Jan 17, 2025 at 08:10:24AM -0500, Jason Merrill wrote:
> > > On 1/16/25 8:04 PM, Marek Polacek wrote:
> > > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
> > > >
> > > > -- >8 --
> > > > The recent r15-6369 unfortunately caused a bad wrong-code issue.
> > > > Here we have
> > > >
> > > > TARGET_EXPR <D.2996, (void) (D.2996 = {.status=0,
> > > > .data={._vptr.Foo=&_ZTV3Foo + 16}})>
> > > >
> > > > and call cp_fold_r -> maybe_constant_init with object=D.2996. In
> > > > cxx_eval_outermost_constant_expr we now take the type of the object
> > > > if present. An object can't have type 'void' and so we continue to
> > > > evaluate the initializer. That evaluates into a VOID_CST, meaning
> > > > we disregard the whole initializer, and terrible things ensue.
> > >
> > > In that case, I'd think we want to use the value of 'object' (which should
> > > be in ctx.ctor?) instead of the return value of
> > > cxx_eval_constant_expression.
> >
> > Ah, I'm sorry I didn't choose that approach. Maybe like this, then?
> >
> > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
>
> OK. Maybe also add an assert that TREE_TYPE (r) is close enough to type?
Thanks. dg.exp passed with this extra assert:
@@ -8986,7 +8986,11 @@ cxx_eval_outermost_constant_expr (tree t, bool
allow_non_constant,
/* If we got a non-simple TARGET_EXPR, the initializer was a sequence
of statements, and the result ought to be stored in ctx.ctor. */
if (r == void_node && !constexpr_dtor && ctx.ctor)
- r = ctx.ctor;
+ {
+ r = ctx.ctor;
+ gcc_checking_assert (same_type_ignoring_top_level_qualifiers_p
+ (TREE_TYPE (r), type));
+ }
if (!constexpr_dtor)
verify_constant (r, allow_non_constant, &non_constant_p, &overflow_p);
OK if the usual testing passes?
Marek
