From 70e9ab23f4ad839bd0979da933101a0da8fbefe9 Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Mon, 25 Feb 2013 23:27:40 -0500
Subject: [PATCH] re PR c++/56438 (ICE in value_dependent_expression_p, at
 cp/pt.c:19551)

	PR c++/56438
	* semantics.c (potential_constant_expression_1): In C++98, a cast
	to non-integral type can't be a constant expression.

From-SVN: r196274
---
 gcc/cp/ChangeLog                      |  6 ++++++
 gcc/cp/semantics.c                    | 12 ++++++++++++
 gcc/testsuite/g++.dg/template/cast3.C | 22 ++++++++++++++++++++++
 3 files changed, 40 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/template/cast3.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index eaa43e1e1b7c..eb98b0446335 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2013-02-25  Jason Merrill  <jason@redhat.com>
+
+	PR c++/56438
+	* semantics.c (potential_constant_expression_1): In C++98, a cast
+	to non-integral type can't be a constant expression.
+
 2013-02-24  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/56403
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 458ed26d330b..60271b511ad0 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -8607,6 +8607,18 @@ potential_constant_expression_1 (tree t, bool want_rval, tsubst_flags_t flags)
     case STATIC_CAST_EXPR:
     case REINTERPRET_CAST_EXPR:
     case IMPLICIT_CONV_EXPR:
+      if (cxx_dialect < cxx0x
+	  && !dependent_type_p (TREE_TYPE (t))
+	  && !INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (t)))
+	/* In C++98, a conversion to non-integral type can't be part of a
+	   constant expression.  */
+	{
+	  if (flags & tf_error)
+	    error ("cast to non-integral type %qT in a constant expression",
+		   TREE_TYPE (t));
+	  return false;
+	}
+
       return (potential_constant_expression_1
 	      (TREE_OPERAND (t, 0),
 	       TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE, flags));
diff --git a/gcc/testsuite/g++.dg/template/cast3.C b/gcc/testsuite/g++.dg/template/cast3.C
new file mode 100644
index 000000000000..b343ee427b32
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/cast3.C
@@ -0,0 +1,22 @@
+// PR c++/56438
+
+struct A { };
+A& operator<<(A&, const char*);
+
+struct B {
+  int size();
+};
+
+struct C { };
+
+template <class S, class T>
+S bar(const S& s, const T& t) {
+  return s;
+}
+
+template<class S, class T>
+void foo() {
+  A a;
+  B b;
+  a << bar(b.size(), C());	// { dg-error "no match" }
+}
-- 
2.47.3