[PR c++/87185] ICE in prune-lambdas

https://gcc.gnu.org/ml/gcc-patches/2018-09/msg00249.html
	cp/
	PR c++/87185
	* lambda.c (prune_lambda_captures): Protect against const_vars.get
	returning NULL.
	testsuite/
	PR c++/87185
	* g++.dg/pr87185.C: New.

From-SVN: r264118

gcc/cp/ChangeLog

+2018-09-05   Pádraig Brady p@draigbrady.com
+
+	PR c++/87185
+	* lambda.c (prune_lambda_captures): Protect against const_vars.get
+	returning NULL.
+
 2018-09-04  Marek Polacek  <polacek@redhat.com>
 
 	* cp-tree.h (treat_lvalue_as_rvalue_p): Declare.

gcc/cp/lambda.c

@@ -1519,8 +1519,8 @@ prune_lambda_captures (tree body)
       tree cap = *capp;
       if (tree var = var_to_maybe_prune (cap))
 	{
-	  tree *use = *const_vars.get (var);
-	  if (TREE_CODE (*use) == DECL_EXPR)
+	  tree **use = const_vars.get (var);
+	  if (use && TREE_CODE (**use) == DECL_EXPR)
 	    {
 	      /* All uses of this capture were folded away, leaving only the
 		 proxy declaration.  */
@@ -1535,7 +1535,7 @@ prune_lambda_captures (tree body)
 	      *fieldp = DECL_CHAIN (*fieldp);
 
 	      /* And remove the capture proxy declaration.  */
-	      *use = void_node;
+	      **use = void_node;
 	      continue;
 	    }
 	}

gcc/testsuite/ChangeLog

+2018-09-05   Pádraig Brady p@draigbrady.com
+
+	PR c++/87185
+	* g++.dg/pr87185.C: New.
+
 2018-09-05  Martin Liska  <mliska@suse.cz>
 
 	PR testsuite/87216

gcc/testsuite/g++.dg/pr87185.C

+// PR c++/87185
+// { dg-do compile { target c++11 } }
+
+void f() { const int i=0; [&]() noexcept {i;}; }