Re: build_x_binary_op (ARRAY_REF ?!

[Alexey Starovoytov <Alexey dot Starovoytov at Sun dot COM>]

On Wed, 19 Apr 2006, Daniel Berlin wrote:

> On Apr 19, 2006, at 4:48 PM, Alexey Starovoytov wrote:
>
> > Hi,
> >
> > Is this a bug that we were lucky not to hit?
> >
> > cp/pt.c:
> >  return build_x_binary_op (ARRAY_REF, op1, RECUR (TREE_OPERAND (t, 1)),
> >                            /*overloaded_p=*/NULL);
> > tree
> > build_x_binary_op (enum tree_code code, tree arg1, tree arg2,
> >                   bool *overloaded_p)
> > {
> >  ...
> >  return build_min_nt (code, arg1, arg2);
> >  ...
> >  return build_min_non_dep (code, expr, orig_arg1, orig_arg2);
> > }
> >
> > the 'code' for build_min* will still be ARRAY_REF, so both functions
> > have a chance to init ARRAY_REF with some junk:
> >  for (i = 0; i < length; i++)
> >    {
> >      tree x = va_arg (p, tree);
> >      TREE_OPERAND (t, i) = x;
> >    }
>
> The returned memory is memset in make_node in tree.c or thereabouts.
> IIRC.

make_node does memset, but the loop above is after the call to make_node.

I guess we didn't hit the problem just because tsubst_copy_and_build()
(where build_x_binary_op (ARRAY_REF is) is never called for array_ref 
when processing_template_decl is non zero.

I guess that sort of assertions need at least a comment or gcc_assert().

Alex.