The constexpr expansion code doesn't understand the C++ front end
statement tree codes; for expanding a constexpr call it expects the
gimplified form. For now let's not bother trying to expand a
statement-expression.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit e01d0162df7b21bb26449e912618a513ecbe18b0
Author: Jason Merrill <ja...@redhat.com>
Date: Wed Jan 21 16:44:24 2015 -0500
PR c++/64701
* constexpr.c (maybe_constant_value): Just hand back STATEMENT_LIST.
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index 7853d37..e3e838e 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -3609,6 +3609,8 @@ maybe_constant_value (tree t, tree decl)
tree r;
if (instantiation_dependent_expression_p (t)
+ /* We can't deal with statements until they've been lowered. */
+ || TREE_CODE (t) == STATEMENT_LIST
|| type_unknown_p (t)
|| BRACE_ENCLOSED_INITIALIZER_P (t)
|| !potential_constant_expression (t))
diff --git a/gcc/testsuite/g++.dg/ext/stmtexpr17.C b/gcc/testsuite/g++.dg/ext/stmtexpr17.C
new file mode 100644
index 0000000..c1640e4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/stmtexpr17.C
@@ -0,0 +1,9 @@
+// PR c++/64701
+// { dg-options "" }
+
+enum { A };
+void
+foo ()
+{
+ int x = ({ do {} while (0); A; });
+}
