Instantiating the compound literal for the underlying array of the
initializer list was creating a new variable, so then we would pull
out that variables initializer and instantiate that, ad infinitum. We
shouldn't need to instantiate the initializer for any artificial
variable.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit 2fb3877338f276ea8f9a8871b823a359672cbc99
Author: Jason Merrill <ja...@redhat.com>
Date: Mon Jul 11 15:01:13 2016 -0400
PR c++/70824 - initializer_list in template
* init.c (constant_value_1): Don't instantiated DECL_INITIAL of
artificial variables.
diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index b4a4388..6047639 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -2073,8 +2073,13 @@ constant_value_1 (tree decl, bool strict_p, bool
return_aggregate_cst_ok_p)
&& TREE_CODE (init) == TREE_LIST
&& TREE_CHAIN (init) == NULL_TREE)
init = TREE_VALUE (init);
- /* Instantiate a non-dependent initializer. */
- init = instantiate_non_dependent_or_null (init);
+ /* Instantiate a non-dependent initializer for user variables. We
+ mustn't do this for the temporary for an array compound literal;
+ trying to instatiate the initializer will keep creating new
+ temporaries until we crash. Probably it's not useful to do it for
+ other artificial variables, either. */
+ if (!DECL_ARTIFICIAL (decl))
+ init = instantiate_non_dependent_or_null (init);
if (!init
|| !TREE_TYPE (init)
|| !TREE_CONSTANT (init)
diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist-template1.C
b/gcc/testsuite/g++.dg/cpp0x/initlist-template1.C
new file mode 100644
index 0000000..a24e205
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/initlist-template1.C
@@ -0,0 +1,15 @@
+// PR c++/70824
+// { dg-do compile { target c++11 } }
+
+#include <initializer_list>
+
+constexpr
+int
+max(std::initializer_list<int> __l)
+{ return *__l.begin(); }
+
+template <class Src>
+void
+a() {
+ const int v = max({1});
+}
