From de69121325ce8e05adb106c87acaeadf1bba61e0 Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Wed, 25 May 2011 16:02:41 -0400
Subject: [PATCH] re PR c++/44311 ([C++0x] no error with switch over enum class
 and integer case)

	PR c++/44311
	* decl.c (case_conversion): New.
	(finish_case_label): Use it.

From-SVN: r174231
---
 gcc/cp/ChangeLog                              |  4 +++
 gcc/cp/decl.c                                 | 34 +++++++++++++++----
 gcc/testsuite/ChangeLog                       |  3 ++
 .../g++.dg/cpp0x/constexpr-switch2.C          | 23 +++++++++++++
 gcc/testsuite/g++.dg/cpp0x/enum15.C           | 20 +++++++++++
 5 files changed, 78 insertions(+), 6 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/constexpr-switch2.C
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/enum15.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index c0677ccf55d..1b611936af4 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,9 @@
 2011-05-25  Jason Merrill  <jason@redhat.com>
 
+	PR c++/44311
+	* decl.c (case_conversion): New.
+	(finish_case_label): Use it.
+
 	* ptree.c (cxx_print_xnode): Handle ARGUMENT_PACK_SELECT.
 
 	PR c++/45698
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 2b6a7770e2d..7fc194554b9 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -2957,6 +2957,28 @@ pop_switch (void)
   free (cs);
 }
 
+/* Convert a case constant VALUE in a switch to the type TYPE of the switch
+   condition.  Note that if TYPE and VALUE are already integral we don't
+   really do the conversion because the language-independent
+   warning/optimization code will work better that way.  */
+
+static tree
+case_conversion (tree type, tree value)
+{
+  if (value == NULL_TREE)
+    return value;
+
+  if (cxx_dialect >= cxx0x
+      && (SCOPED_ENUM_P (type)
+	  || !INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (TREE_TYPE (value))))
+    {
+      if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type))
+	type = type_promotes_to (type);
+      value = perform_implicit_conversion (type, value, tf_warning_or_error);
+    }
+  return cxx_constant_value (value);
+}
+
 /* Note that we've seen a definition of a case label, and complain if this
    is a bad place for one.  */
 
@@ -2965,6 +2987,7 @@ finish_case_label (location_t loc, tree low_value, tree high_value)
 {
   tree cond, r;
   struct cp_binding_level *p;
+  tree type;
 
   if (processing_template_decl)
     {
@@ -2984,13 +3007,12 @@ finish_case_label (location_t loc, tree low_value, tree high_value)
   if (!check_switch_goto (switch_stack->level))
     return error_mark_node;
 
-  if (low_value)
-    low_value = cxx_constant_value (low_value);
-  if (high_value)
-    high_value = cxx_constant_value (high_value);
+  type = SWITCH_STMT_TYPE (switch_stack->switch_stmt);
+
+  low_value = case_conversion (type, low_value);
+  high_value = case_conversion (type, high_value);
 
-  r = c_add_case_label (loc, switch_stack->cases, cond,
-			SWITCH_STMT_TYPE (switch_stack->switch_stmt),
+  r = c_add_case_label (loc, switch_stack->cases, cond, type,
 			low_value, high_value);
 
   /* After labels, make any new cleanups in the function go into their
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2a30f6e8bbc..e8a335ff813 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2011-05-25  Jason Merrill  <jason@redhat.com>
 
+	* g++.dg/cpp0x/enum15.C: New.
+	* g++.dg/cpp0x/constexpr-switch2.C: New.
+
 	* g++.dg/cpp0x/variadic110.C: New.
 
 	* g++.dg/cpp0x/auto9.C: Add typedef test.
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-switch2.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-switch2.C
new file mode 100644
index 00000000000..55cf2ad7ce8
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-switch2.C
@@ -0,0 +1,23 @@
+// Test for constexpr conversion in case context
+// { dg-options -std=c++0x }
+
+enum class E { e1, e2 };
+
+struct A
+{
+  E e;
+  constexpr operator E() { return e; }
+  constexpr A(E e): e(e) { }
+};
+
+E e;
+
+int main()
+{
+  switch (e)
+    {
+    case A(E::e1):
+    case A(E::e2):
+      ;
+    }
+}
diff --git a/gcc/testsuite/g++.dg/cpp0x/enum15.C b/gcc/testsuite/g++.dg/cpp0x/enum15.C
new file mode 100644
index 00000000000..d653216498e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/enum15.C
@@ -0,0 +1,20 @@
+// PR c++/44311
+// { dg-options -std=c++0x }
+
+enum class A { Val0, Val1 };
+
+void foo (A a, int i)
+{
+  switch (a)
+    {
+    case A::Val0: break;
+    case 1: break;		// { dg-error "" }
+    }
+
+  switch (i)
+    {
+    case A::Val0: break;	// { dg-error "" }
+    case 1: break;
+    case 2.0: break;
+    }
+}
-- 
2.30.2