https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113083
--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
What about:
2024-02-22 Jakub Jelinek <ja...@redhat.com>
PR c++/113083
* cp-gimplify.cc (cp_fold): For targetm.cxx.cdtor_returns_this ()
wrap r into a COMPOUND_EXPR and return folded CALL_EXPR_ARG (x, 0).
* g++.dg/cpp0x/constexpr-113083.C: New test.
--- gcc/cp/cp-gimplify.cc.jj 2024-02-22 21:45:09.663430066 +0100
+++ gcc/cp/cp-gimplify.cc 2024-02-22 22:16:41.816591451 +0100
@@ -3415,6 +3415,10 @@ cp_fold (tree x, fold_flags_t flags)
tree s = build_fold_indirect_ref_loc (loc,
CALL_EXPR_ARG (x, 0));
r = cp_build_init_expr (s, r);
+ if (targetm.cxx.cdtor_returns_this ())
+ r = build2 (COMPOUND_EXPR, TREE_TYPE (x), r,
+ fold_convert (TREE_TYPE (x),
+ CALL_EXPR_ARG (x, 0)));
}
x = r;
break;
--- gcc/testsuite/g++.dg/cpp0x/constexpr-113083.C.jj 2024-01-13
00:05:00.077372302 +0100
+++ gcc/testsuite/g++.dg/cpp0x/constexpr-113083.C 2024-02-22
22:20:20.622618992 +0100
@@ -0,0 +1,16 @@
+// PR c++/113083
+// { dg-do compile { target c++11 } }
+// { dg-options "-Os" }
+
+struct A { constexpr A (); };
+
+void
+foo ()
+{
+ A b;
+}
+
+constexpr
+A::A ()
+{
+}
Though, perhaps we need cp_save_expr in that case to make sure if there were
side-effects in CALL_EXPR (x, 0) that we wouldn't evaluate them twice.
