On Thu, Jan 27, 2022 at 10:17:00PM -0500, Jason Merrill wrote:
> On 1/27/22 20:02, Marek Polacek wrote:
> > @@ -11159,8 +11159,16 @@ create_array_type_for_decl (tree name, tree type,
> > tree size, location_t loc)
> > /* Figure out the index type for the array. */
> > if (size)
> > - itype = compute_array_index_type_loc (loc, name, size,
> > - tf_warning_or_error);
> > + {
> > + itype = compute_array_index_type_loc (loc, name, size,
> > + tf_warning_or_error);
> > + if (type_uses_auto (type)
> > + && !TREE_CONSTANT (maybe_constant_value (size)))
>
> Maybe variably_modified_type_p (itype)?
Ah yes, I missed that v_m_t_p actually looks at TYPE_MAX_VALUE...
Fixed.
> > + {
> > + sorry_at (loc, "variable-length array of %<auto%>");
> > + return error_mark_node;
> > + }
> > + }
> > return build_cplus_array_type (type, itype);
> > }
> > diff --git a/gcc/testsuite/g++.dg/cpp23/auto-array3.C
> > b/gcc/testsuite/g++.dg/cpp23/auto-array3.C
> > new file mode 100644
> > index 00000000000..e383a17d0ee
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/cpp23/auto-array3.C
> > @@ -0,0 +1,17 @@
> > +// PR c++/102414
> > +// { dg-do compile { target c++11 } }
> > +// { dg-options "" }
> > +
> > +constexpr int sz () { return 3; }
> > +
> > +void f ()
> > +{
> > + int a[3];
> > + auto (*a1)[0/0] = &a; // { dg-message "variable-length array of .auto." }
> > +// { dg-warning "division by zero" "" { target *-*-* } .-1 }
>
> Let's move the error into the other testcase?
Done.
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
-- >8 --
Here we ICE in unify_array_domain when we're trying to deduce the type
of an array, as in
auto(*p)[i] = (int(*)[i])0;
but unify_array_domain doesn't arbitrarily complex bounds. Another
test is, e.g.,
auto (*b)[0/0] = &a;
where the type of the array is
<<< Unknown tree: template_type_parm >>>[0:(sizetype) ((ssizetype) (0 / 0) -
1)]
It seems to me that we need not handle these.
PR c++/102414
PR c++/101874
gcc/cp/ChangeLog:
* decl.cc (create_array_type_for_decl): Use template_placeholder_p.
Sorry on a variable-length array of auto.
gcc/testsuite/ChangeLog:
* g++.dg/cpp23/auto-array3.C: New test.
* g++.dg/cpp23/auto-array4.C: New test.
---
gcc/cp/decl.cc | 14 +++++++++++---
gcc/testsuite/g++.dg/cpp23/auto-array3.C | 16 ++++++++++++++++
gcc/testsuite/g++.dg/cpp23/auto-array4.C | 14 ++++++++++++++
3 files changed, 41 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp23/auto-array3.C
create mode 100644 gcc/testsuite/g++.dg/cpp23/auto-array4.C
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 26ce9bfefec..09eed9ceba6 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -11099,7 +11099,7 @@ create_array_type_for_decl (tree name, tree type, tree
size, location_t loc)
/* [dcl.type.class.deduct] prohibits forming an array of placeholder
for a deduced class type. */
- if (is_auto (type) && CLASS_PLACEHOLDER_TEMPLATE (type))
+ if (template_placeholder_p (type))
{
if (name)
error_at (loc, "%qD declared as array of template placeholder "
@@ -11169,8 +11169,16 @@ create_array_type_for_decl (tree name, tree type, tree
size, location_t loc)
/* Figure out the index type for the array. */
if (size)
- itype = compute_array_index_type_loc (loc, name, size,
- tf_warning_or_error);
+ {
+ itype = compute_array_index_type_loc (loc, name, size,
+ tf_warning_or_error);
+ if (type_uses_auto (type)
+ && variably_modified_type_p (itype, /*fn=*/NULL_TREE))
+ {
+ sorry_at (loc, "variable-length array of %<auto%>");
+ return error_mark_node;
+ }
+ }
return build_cplus_array_type (type, itype);
}
diff --git a/gcc/testsuite/g++.dg/cpp23/auto-array3.C
b/gcc/testsuite/g++.dg/cpp23/auto-array3.C
new file mode 100644
index 00000000000..fdf25470fc2
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/auto-array3.C
@@ -0,0 +1,16 @@
+// PR c++/102414
+// PR c++/101874
+// { dg-do compile { target c++11 } }
+// { dg-options "" }
+
+constexpr int sz () { return 3; }
+
+void f ()
+{
+ int a[3];
+ const int N = 3;
+ auto (*a2)[N] = &a;
+ constexpr int M = 3;
+ auto (*a3)[M] = &a;
+ auto (*a4)[sz()] = &a;
+}
diff --git a/gcc/testsuite/g++.dg/cpp23/auto-array4.C
b/gcc/testsuite/g++.dg/cpp23/auto-array4.C
new file mode 100644
index 00000000000..4385c4a6bf9
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp23/auto-array4.C
@@ -0,0 +1,14 @@
+// PR c++/102414
+// PR c++/101874
+// { dg-do compile { target c++11 } }
+// { dg-options "" }
+
+void
+f (int i)
+{
+ auto x[i] = { 0 }; // { dg-message "variable-length array of .auto." }
+ auto(*p)[i] = (int(*)[i])0; // { dg-message "variable-length array of
.auto." }
+ int a[3];
+ auto (*a1)[0/0] = &a; // { dg-message "variable-length array of .auto." }
+// { dg-warning "division by zero" "" { target *-*-* } .-1 }
+}
base-commit: 3a5fdf986dc6ebb6e244087b462132590ad0a184
--
2.34.1
