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C++ PATCH for c++/70824 (initializer list in template)

Message ID CADzB+2ne8-7CKvqBTVuOdyQRmCU=WPkUEUZ9KnjC_g5VM-4Cxg@mail.gmail.com
State New
Headers show

Commit Message

Jason Merrill July 15, 2016, 4:44 p.m. UTC 
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 <jason@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.
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Patch

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});
+}