re PR c++/89405 (ICE in import_export_decl, at cp/decl2.c:2959)

	PR c++/89405
	* decl.c (maybe_commonize_var): When clearing TREE_PUBLIC and
	DECL_COMMON, set DECL_INTERFACE_KNOWN.

	* g++.dg/cpp1z/inline-var5.C: New test.

From-SVN: r269058

gcc/cp/ChangeLog

 2019-02-20  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/89405
+	* decl.c (maybe_commonize_var): When clearing TREE_PUBLIC and
+	DECL_COMMON, set DECL_INTERFACE_KNOWN.
+
 	PR c++/89336
 	* constexpr.c (cxx_eval_store_expression): Diagnose changing of active
 	union member for -std=c++17 and earlier.

gcc/cp/decl.c

@@ -5634,6 +5634,7 @@ maybe_commonize_var (tree decl)
 		 be merged.  */
 	      TREE_PUBLIC (decl) = 0;
 	      DECL_COMMON (decl) = 0;
+	      DECL_INTERFACE_KNOWN (decl) = 1;
 	      const char *msg;
 	      if (DECL_INLINE_VAR_P (decl))
 		msg = G_("sorry: semantics of inline variable "

gcc/testsuite/ChangeLog

 2019-02-20  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/89405
+	* g++.dg/cpp1z/inline-var5.C: New test.
+
 	PR middle-end/89412
 	* gcc.c-torture/compile/pr89412.c: New test.
 

gcc/testsuite/g++.dg/cpp1z/inline-var5.C

+// PR c++/89405
+// { dg-do compile { target c++17 } }
+// { dg-options "-fno-weak" }
+
+template <int N>
+struct S
+{
+  static constexpr int a = N;	// { dg-warning "semantics of inline variable" }
+};				// { dg-message "you can work around this" "" { target *-*-* } .-1 }
+
+const int *x = &S<0>::a;