re PR c++/85208 (ICE with #pragma weak and structured binding)

	PR c++/85208
	* decl.c (start_decl): For DECL_DECOMPOSITION_P decls, don't call
	maybe_apply_pragma_weak here...
	(cp_maybe_mangle_decomp): ... but call it here instead.

	* g++.dg/cpp1z/decomp41.C: New test.

From-SVN: r259155

gcc/cp/ChangeLog

+2018-04-05  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/85208
+	* decl.c (start_decl): For DECL_DECOMPOSITION_P decls, don't call
+	maybe_apply_pragma_weak here...
+	(cp_maybe_mangle_decomp): ... but call it here instead.
+
 2018-04-05  Jason Merrill  <jason@redhat.com>
 
 	PR c++/85136 - ICE with designated init in template.

gcc/cp/decl.c

@@ -5090,7 +5090,7 @@ start_decl (const cp_declarator *declarator,
     }
 
   /* If #pragma weak was used, mark the decl weak now.  */
-  if (!processing_template_decl)
+  if (!processing_template_decl && !DECL_DECOMPOSITION_P (decl))
     maybe_apply_pragma_weak (decl);
 
   if (TREE_CODE (decl) == FUNCTION_DECL
@@ -7510,6 +7510,7 @@ cp_maybe_mangle_decomp (tree decl, tree first, unsigned int count)
       for (unsigned int i = 0; i < count; i++, d = DECL_CHAIN (d))
 	v[count - i - 1] = d;
       SET_DECL_ASSEMBLER_NAME (decl, mangle_decomp (decl, v));
+      maybe_apply_pragma_weak (decl);
     }
 }
 

gcc/testsuite/ChangeLog

 2018-04-05  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/85208
+	* g++.dg/cpp1z/decomp41.C: New test.
+
 	PR middle-end/85195
 	* gcc.dg/pr85195.c: New test.
 

gcc/testsuite/g++.dg/cpp1z/decomp41.C

+// PR c++/85208
+// { dg-do compile { target c++11 } }
+// { dg-require-weak "" }
+// { dg-options "" }
+
+#pragma weak _ZDC1d1e1fE
+struct A { int i, j, k; };
+auto [a, b, c] = A ();	// { dg-warning "structured bindings only available with" "" { target c++14_down } }
+auto [d, e, f] = A ();	// { dg-warning "structured bindings only available with" "" { target c++14_down } }