c++: Fix up VEC_INIT_EXPR gimplification after r12-7069

During patch backporting, I've noticed that while most cp_walk_tree calls
with cp_fold_r callback callers were changed from &pset to cp_fold_data
&data, the VEC_INIT_EXPR gimplifications has not, so it still passes just
address of a hash_set<tree> and so if during the folding we ever touch
data->flags, we use uninitialized data there.

The following patch changes it to do the same thing as cp_fold_function
because the VEC_INIT_EXPR gimplifications will happen on function bodies
only.

2023-05-03  Jakub Jelinek  <jakub@redhat.com>

	* cp-gimplify.cc (cp_fold_data): Move definition earlier.
	(cp_gimplify_expr): Pass address of ff_genericize | ff_mce_false
	constructed data rather than &pset to cp_walk_tree with cp_fold_r.

diff --git a/gcc/cp/cp-gimplify.cc b/gcc/cp/cp-gimplify.cc
index 4fecd5616bd419ba6e5c50ab2d10fabd00e6eb02..1216ef17b081d2ae61c1612336cb5378b7d9ca40 100644 (file)
--- a/gcc/cp/cp-gimplify.cc
+++ b/gcc/cp/cp-gimplify.cc
@@ -57,6 +57,13 @@ enum fold_flags {
 
 using fold_flags_t = int;
 
+struct cp_fold_data
+{
+  hash_set<tree> pset;
+  fold_flags_t flags;
+  cp_fold_data (fold_flags_t flags): flags (flags) {}
+};
+
 /* Forward declarations.  */
 
 static tree cp_genericize_r (tree *, int *, void *);
@@ -505,8 +512,8 @@ cp_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
        *expr_p = expand_vec_init_expr (NULL_TREE, *expr_p,
                                        tf_warning_or_error);
 
-       hash_set<tree> pset;
-       cp_walk_tree (expr_p, cp_fold_r, &pset, NULL);
+       cp_fold_data data (ff_genericize | ff_mce_false);
+       cp_walk_tree (expr_p, cp_fold_r, &data, NULL);
        cp_genericize_tree (expr_p, false);
        copy_if_shared (expr_p);
        ret = GS_OK;
@@ -1029,13 +1036,6 @@ struct cp_genericize_data
      in fold-const, we need to perform this before transformation to
      GIMPLE-form.  */
 
-struct cp_fold_data
-{
-  hash_set<tree> pset;
-  fold_flags_t flags;
-  cp_fold_data (fold_flags_t flags): flags (flags) {}
-};
-
 static tree
 cp_fold_r (tree *stmt_p, int *walk_subtrees, void *data_)
 {