[gcc r9-10173] c++: NRV and ref-extended temps [PR101442]

[gcc r9-10173] c++: NRV and ref-extended temps [PR101442]

[Jason Merrill]

https://gcc.gnu.org/g:48b8d5e028abee8869de946bbd7d24d746655d88

commit r9-10173-g48b8d5e028abee8869de946bbd7d24d746655d88
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 7fb669fd48f..bf732ba65cd 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -7442,7 +7442,7 @@ 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 dc9145892c4..8e60b947397 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -878,7 +878,7 @@ 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);
       release_tree_vector (cleanups);
     }
   else if (type_build_ctor_call (type)
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 596dc4d6447..579bfcbdc5c 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -476,7 +476,8 @@ 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();
+}