[gcc r11-9995] c++: NRV and ref-extended temps [PR101442]

[gcc r11-9995] c++: NRV and ref-extended temps [PR101442]

[Jason Merrill]

https://gcc.gnu.org/g:f9e356458d8f14b5a82f3244385ce814903fc02b

commit r11-9995-gf9e356458d8f14b5a82f3244385ce814903fc02b
Author: Jason Merrill <jason@redhat.com>
Date:   Wed Apr 13 13:23:08 2022 -0400

    c++: NRV and ref-extended temps [PR101442]
    
    This issue goes back to r83221, where the cleanup for extended ref temps
    changed from being unconditional to being tied to the declaration they
    formed part of the initializer for.
    
    The named return value optimization changes the cleanup for the NRV variable
    to only run on the EH path; we don't want that change to affect temporary
    cleanups.  The perform_member_init change isn't necessary (there 'decl' is a
    COMPONENT_REF), it's just for consistency.
    
            PR c++/101442
    
    gcc/cp/ChangeLog:
    
            * decl.c (cp_finish_decl): Don't pass decl to push_cleanup.
            * init.c (perform_member_init): Likewise.
            * semantics.c (push_cleanup): Adjust comment.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/cpp0x/initlist-nrv1.C: New test.

Diff:
---
 gcc/cp/decl.c                              |  2 +-
 gcc/cp/init.c                              |  2 +-
 gcc/cp/semantics.c                         |  3 ++-
 gcc/testsuite/g++.dg/cpp0x/initlist-nrv1.C | 34 ++++++++++++++++++++++++++++++
 4 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index bf257a793d5..bb6535a415b 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -8312,7 +8312,7 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
     {
       unsigned i; tree t;
       FOR_EACH_VEC_ELT (*cleanups, i, t)
-	push_cleanup (decl, t, false);
+	push_cleanup (NULL_TREE, t, false);
       release_tree_vector (cleanups);
     }
 
diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index 814dba4e4cd..f694c9a5776 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -911,7 +911,7 @@ perform_member_init (tree member, tree init)
       init = build2 (INIT_EXPR, type, decl, init);
       finish_expr_stmt (init);
       FOR_EACH_VEC_ELT (*cleanups, i, t)
-	push_cleanup (decl, t, false);
+	push_cleanup (NULL_TREE, t, false);
     }
   else if (type_build_ctor_call (type)
 	   || (init && CLASS_TYPE_P (strip_array_types (type))))
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 36ad96febf3..baae5a0f1e4 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -655,7 +655,8 @@ do_pushlevel (scope_kind sk)
 
 /* Queue a cleanup.  CLEANUP is an expression/statement to be executed
    when the current scope is exited.  EH_ONLY is true when this is not
-   meant to apply to normal control flow transfer.  */
+   meant to apply to normal control flow transfer.  DECL is the VAR_DECL
+   being cleaned up, if any, or null for temporaries or subobjects.  */
 
 void
 push_cleanup (tree decl, tree cleanup, bool eh_only)
diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist-nrv1.C b/gcc/testsuite/g++.dg/cpp0x/initlist-nrv1.C
new file mode 100644
index 00000000000..e44dbecfece
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/initlist-nrv1.C
@@ -0,0 +1,34 @@
+// PR c++/101442
+// { dg-do run { target c++11 } }
+
+bool destroyed = false;
+
+struct A
+{
+  A() {}
+  A(const A &) = delete;
+  A &operator=(const A &) = delete;
+  ~A() {destroyed = true;}
+};
+
+struct B
+{
+  const A &a;
+  struct string {
+    string(const char*) { }
+    ~string() { }
+  } s;
+};
+
+B foo()
+{
+  B ret{ A{}, "" };
+  return ret;
+}
+
+int main()
+{
+  B b = foo();
+  if (!destroyed)
+    __builtin_abort();
+}