[gcc r12-8150] c++: NRV and ref-extended temps [PR101442]

[gcc r12-8150] c++: NRV and ref-extended temps [PR101442]

[Jason Merrill]

https://gcc.gnu.org/g:ad8161e6d7b26d690d90069ae9a129e7ac36892a

commit r12-8150-gad8161e6d7b26d690d90069ae9a129e7ac36892a
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.cc (cp_finish_decl): Don't pass decl to push_cleanup.
            * init.cc (perform_member_init): Likewise.
            * semantics.cc (push_cleanup): Adjust comment.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/cpp0x/initlist-nrv1.C: New test.

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

diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 5f59612fb00..d51fd75b003 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -8554,7 +8554,7 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
     {
       for (tree t : *cleanups)
 	{
-	  push_cleanup (decl, t, false);
+	  push_cleanup (NULL_TREE, t, false);
 	  /* As in initialize_local_var.  */
 	  wrap_temporary_cleanups (init, t);
 	}
diff --git a/gcc/cp/init.cc b/gcc/cp/init.cc
index 7ce8d3a46e5..75ab965a218 100644
--- a/gcc/cp/init.cc
+++ b/gcc/cp/init.cc
@@ -1066,7 +1066,7 @@ perform_member_init (tree member, tree init, hash_set<tree> &uninitialized)
       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.cc b/gcc/cp/semantics.cc
index 43627ed30af..f5ec808b1bc 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -666,7 +666,8 @@ 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();
+}