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C++ PATCH for c++/48089 (ICE with invalid constexpr ctor)
- From: Jason Merrill <jason at redhat dot com>
- To: gcc-patches List <gcc-patches at gcc dot gnu dot org>
- Date: Wed, 16 Mar 2011 22:32:34 -0400
- Subject: C++ PATCH for c++/48089 (ICE with invalid constexpr ctor)
In a normal constexpr function, we treat *this as a potential constant
expression. But in a constexpr constructor it isn't, since we're still
in the process of initializing the object.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit 0f23f8a6fca94b1a00a51ea34643268e9ff840e9
Author: Jason Merrill <jason@redhat.com>
Date: Wed Mar 16 20:55:52 2011 -0400
PR c++/48089
* semantics.c (potential_constant_expression_1): Don't allow *this
in a constructor.
(register_constexpr_fundef): Use potential_rvalue_constant_expression.
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index a0c5ae3..7519d26 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -5674,11 +5674,11 @@ register_constexpr_fundef (tree fun, tree body)
body = unshare_expr (TREE_OPERAND (body, 0));
}
- if (!potential_constant_expression (body))
+ if (!potential_rvalue_constant_expression (body))
{
DECL_DECLARED_CONSTEXPR_P (fun) = false;
if (!DECL_TEMPLATE_INSTANTIATION (fun))
- require_potential_constant_expression (body);
+ require_potential_rvalue_constant_expression (body);
return NULL;
}
fundef->body = body;
@@ -7496,7 +7496,16 @@ potential_constant_expression_1 (tree t, bool want_rval, tsubst_flags_t flags)
tree x = TREE_OPERAND (t, 0);
STRIP_NOPS (x);
if (is_this_parameter (x))
- return true;
+ {
+ if (DECL_CONSTRUCTOR_P (DECL_CONTEXT (x)) && want_rval)
+ {
+ if (flags & tf_error)
+ error ("the value of the object being constructed is "
+ "not a constant expression");
+ return false;
+ }
+ return true;
+ }
return potential_constant_expression_1 (x, rval, flags);
}
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-48089.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-48089.C
new file mode 100644
index 0000000..88ef3d6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-48089.C
@@ -0,0 +1,9 @@
+// PR c++/48089
+// { dg-options -std=c++0x }
+
+struct s {
+ constexpr s() : v(v) { } // { dg-error "object being constructed" }
+ char v;
+};
+
+s bang;