re PR preprocessor/83602 (ICE in cpp_macro_definition_location(cpp_hashnode*) on invalid code)

	PR preprocessor/83602
	* name-lookup.c (lookup_name_fuzzy): Don't use macro_use_before_def
	for builtin macros.

	* g++.dg/cpp/pr83602.C: New test.

From-SVN: r256175

gcc/cp/ChangeLog

 2018-01-03  Jakub Jelinek  <jakub@redhat.com>
 
+	PR preprocessor/83602
+	* name-lookup.c (lookup_name_fuzzy): Don't use macro_use_before_def
+	for builtin macros.
+
 	PR c++/83634
 	* cp-gimplify.c (cp_fold) <case NOP_EXPR>: If the operand folds to
 	error_mark_node, return error_mark_node.

gcc/cp/name-lookup.c

@@ -5757,7 +5757,7 @@ lookup_name_fuzzy (tree name, enum lookup_name_fuzzy_kind kind, location_t loc)
       /* If we have an exact match for a macro name, then the
 	 macro has been used before it was defined.  */
       cpp_hashnode *macro = bmm.blithely_get_best_candidate ();
-      if (macro)
+      if (macro && (macro->flags & NODE_BUILTIN) == 0)
 	return name_hint (NULL,
 			  new macro_use_before_def (loc, macro));
     }

gcc/testsuite/ChangeLog

 2018-01-03  Jakub Jelinek  <jakub@redhat.com>
 
+	PR preprocessor/83602
+	* g++.dg/cpp/pr83602.C: New test.
+
 	PR c++/83634
 	* g++.dg/parse/pr83634.C: New test.
 

gcc/testsuite/g++.dg/cpp/pr83602.C

+// PR preprocessor/83602
+// { dg-do compile }
+
+_Pragma	// { dg-error "_Pragma" }