[Bug c++/113083] [14 Regression][arm] ICE in fold_convert_loc, at fold-const.cc:2602 since r14-5979-g99d114c15523e0

["jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113083

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
As in:
2024-02-22  Jakub Jelinek  <jakub@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 22:30:23.481428242 +0100
@@ -3412,9 +3412,15 @@ cp_fold (tree x, fold_flags_t flags)
            if (DECL_CONSTRUCTOR_P (callee))
              {
                loc = EXPR_LOCATION (x);
-               tree s = build_fold_indirect_ref_loc (loc,
-                                                     CALL_EXPR_ARG (x, 0));
+               tree a = CALL_EXPR_ARG (x, 0);
+               bool return_this = targetm.cxx.cdtor_returns_this ();
+               if (return_this)
+                 a = cp_save_expr (a);
+               tree s = build_fold_indirect_ref_loc (loc, a);
                r = cp_build_init_expr (s, r);
+               if (return_this)
+                 r = build2_loc (loc, COMPOUND_EXPR, TREE_TYPE (x), r,
+                                 fold_convert_loc (loc, TREE_TYPE (x), a));
              }
            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 ()
+{
+}