diff --git a/gcc/analyzer/diagnostic-manager.cc b/gcc/analyzer/diagnostic-manager.cc
index 08d92f9780e..8002d0757da 100644
--- a/gcc/analyzer/diagnostic-manager.cc
+++ b/gcc/analyzer/diagnostic-manager.cc
@@ -678,12 +678,12 @@ saved_diagnostic::saved_diagnostic (const state_machine *sm,
   m_stmt (ploc.m_stmt),
   /* stmt_finder could be on-stack; we want our own copy that can
      outlive that.  */
-  m_stmt_finder (ploc.m_finder ? ploc.m_finder->clone () : NULL),
+  m_stmt_finder (ploc.m_finder ? ploc.m_finder->clone () : nullptr),
   m_loc (ploc.m_loc),
   m_var (var), m_sval (sval), m_state (state),
-  m_d (std::move (d)), m_trailing_eedge (NULL),
+  m_d (std::move (d)), m_trailing_eedge (nullptr),
   m_idx (idx),
-  m_best_epath (NULL), m_problem (NULL),
+  m_best_epath (nullptr), m_problem (nullptr),
   m_notes ()
 {
   /* We must have an enode in order to be able to look for paths
@@ -1790,10 +1790,10 @@ public:
 					stmt,
 					stack_depth,
 					sm,
-					NULL,
+					nullptr,
 					src_sm_val,
 					dst_sm_val,
-					NULL,
+					nullptr,
 					dst_state,
 					src_node));
     return false;
@@ -1983,9 +1983,9 @@ struct null_assignment_sm_context : public sm_context
 					m_sm,
 					var_new_sval,
 					from, to,
-					NULL,
+					nullptr,
 					*m_new_state,
-					NULL));
+					nullptr));
   }
 
   void set_next_state (const gimple *stmt,
@@ -2009,9 +2009,9 @@ struct null_assignment_sm_context : public sm_context
 					m_sm,
 					sval,
 					from, to,
-					NULL,
+					nullptr,
 					*m_new_state,
-					NULL));
+					nullptr));
   }
 
   void warn (const supernode *, const gimple *,
diff --git a/gcc/analyzer/infinite-loop.cc b/gcc/analyzer/infinite-loop.cc
index e277a8384a0..9a98d5b156e 100644
--- a/gcc/analyzer/infinite-loop.cc
+++ b/gcc/analyzer/infinite-loop.cc
@@ -225,7 +225,7 @@ public:
 			enode->get_function ()->decl,
 			enode->get_stack_depth ()),
 	enode,
-	NULL, NULL, NULL));
+	nullptr, nullptr, nullptr));
 
     logger *logger = emission_path->get_logger ();
 
diff --git a/gcc/analyzer/infinite-recursion.cc b/gcc/analyzer/infinite-recursion.cc
index 65f136ddad6..2e0c4ef7325 100644
--- a/gcc/analyzer/infinite-recursion.cc
+++ b/gcc/analyzer/infinite-recursion.cc
@@ -195,7 +195,7 @@ public:
 			m_callee_fndecl,
 			m_new_entry_enode->get_stack_depth ()),
 	enode,
-	NULL, NULL, NULL));
+	nullptr, nullptr, nullptr));
   }
 
   /* Reject paths in which conjured svalues have affected control flow
diff --git a/gcc/analyzer/varargs.cc b/gcc/analyzer/varargs.cc
index 3348121a0ef..f24e35fb491 100644
--- a/gcc/analyzer/varargs.cc
+++ b/gcc/analyzer/varargs.cc
@@ -630,7 +630,7 @@ va_list_state_machine::on_va_end (sm_context *sm_ctxt,
 std::unique_ptr<pending_diagnostic>
 va_list_state_machine::on_leak (tree var) const
 {
-  return make_unique<va_list_leak> (*this, NULL, var);
+  return make_unique<va_list_leak> (*this, nullptr, var);
 }
 
 } // anonymous namespace
diff --git a/gcc/rust/metadata/rust-imports.cc b/gcc/rust/metadata/rust-imports.cc
index 17451fbcb9b..7da245587ae 100644
--- a/gcc/rust/metadata/rust-imports.cc
+++ b/gcc/rust/metadata/rust-imports.cc
@@ -179,7 +179,7 @@ Import::try_package_in_directory (const std::string &filename,
 		   "%s exists but does not contain any Rust export data",
 		   found_filename.c_str ());
 
-  return std::make_pair (NULL, macros);
+  return std::make_pair (nullptr, macros);
 }
 
 // Given import "*PFILENAME", where *PFILENAME does not exist, try
diff --git a/gcc/value-pointer-equiv.cc b/gcc/value-pointer-equiv.cc
index bfc940ec991..cfb53ab4eee 100644
--- a/gcc/value-pointer-equiv.cc
+++ b/gcc/value-pointer-equiv.cc
@@ -62,7 +62,7 @@ public:
 private:
   auto_vec<std::pair <tree, tree>> m_stack;
   auto_vec<tree> m_replacements;
-  const std::pair <tree, tree> m_marker = std::make_pair (NULL, NULL);
+  const std::pair <tree, tree> m_marker = std::make_pair (NULL_TREE, NULL_TREE);
 };
 
 ssa_equiv_stack::ssa_equiv_stack ()