https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108880
--- Comment #12 from Marek Polacek <mpolacek at gcc dot gnu.org> --- Sure, it worked for the testcase because the STATEMENT_LIST only had two stmts. I'm testing: --- a/gcc/c-family/c-gimplify.cc +++ b/gcc/c-family/c-gimplify.cc @@ -516,7 +516,8 @@ c_genericize_control_stmt (tree *stmt_p, int *walk_subtrees, void *data, tree t = tsi_stmt (i); if (TREE_CODE (t) != DEBUG_BEGIN_STMT && nondebug_stmts < 2) nondebug_stmts++; - walk_tree_1 (tsi_stmt_ptr (i), func, data, NULL, lh); + walk_tree_1 (tsi_stmt_ptr (i), func, data, + static_cast<hash_set<tree> *>(data), lh); if (TREE_CODE (t) != DEBUG_BEGIN_STMT && (nondebug_stmts > 1 || TREE_SIDE_EFFECTS (tsi_stmt (i)))) clear_side_effects = false; @@ -572,8 +573,9 @@ c_genericize (tree fndecl) bc_state_t save_state; push_cfun (DECL_STRUCT_FUNCTION (fndecl)); save_bc_state (&save_state); - walk_tree_without_duplicates (&DECL_SAVED_TREE (fndecl), - c_genericize_control_r, NULL); + hash_set<tree> pset; + walk_tree (&DECL_SAVED_TREE (fndecl), c_genericize_control_r, &pset, + &pset); restore_bc_state (&save_state); pop_cfun (); }