PR c++/52988

	* typeck.c (decay_conversion): Don't discard side-effects from
	expressions of nullptr_t.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-4_6-branch@188953 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 28 insertions, 1 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 87870dfcf74..c5387511679 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2012-06-25  Jason Merrill  <jason@redhat.com>
+
+	PR c++/52988
+	* typeck.c (decay_conversion): Don't discard side-effects from
+	expressions of nullptr_t.
+
 2012-04-04  Steve Ellcey <sje@cup.hp.com>
 
 	Backported from mainline.
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index deb895111b6..b2a08a3b9e8 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -1822,7 +1822,7 @@ decay_conversion (tree exp)
   if (error_operand_p (exp))
     return error_mark_node;
 
-  if (NULLPTR_TYPE_P (type))
+  if (NULLPTR_TYPE_P (type) && !TREE_SIDE_EFFECTS (exp))
     return nullptr_node;
 
   /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a4fb57c915c..33920f8651a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2012-06-25  Jason Merrill  <jason@redhat.com>
+
+	PR c++/52988
+	* g++.dg/cpp0x/nullptr28.C: New.
+
 2012-06-19  Kaz Kojima  <kkojima@gcc.gnu.org>
 
 	* gcc.dg/stack-usage-1.c: Remove dg-options line for sh targets
diff --git a/gcc/testsuite/g++.dg/cpp0x/nullptr28.C b/gcc/testsuite/g++.dg/cpp0x/nullptr28.C
new file mode 100644
index 00000000000..05fbe57b197
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/nullptr28.C
@@ -0,0 +1,16 @@
+// { dg-do run { target c++11 } }
+
+typedef decltype(nullptr) nullptr_t;
+
+int i;
+nullptr_t n;
+const nullptr_t& f() { ++i; return n; }
+
+nullptr_t g() { return f(); }
+
+int main()
+{
+  g();
+  if (i != 1)
+    __builtin_abort ();
+}