On 10/11/22 16:00, Marek Polacek wrote:
Since r12-8066, in cxx_eval_vec_init we perform expand_vec_init_expr while processing the default argument in this test.
Hmm, why are we calling cxx_eval_vec_init during parsing of the default argument? In particular, any expansion that depends on the enclosing function context should be deferred until the default arg is used by a call.
But it's certainly true that the "function_body" test is wrong in this situation; you might move the c_f_d test into the calculation of that variable. The patch is OK with that change, but please also answer my question above.
At this point start_preparsed_function hasn't yet set current_function_decl. expand_vec_init_expr then leads to maybe_splice_retval_cleanup which checks DECL_CONSTRUCTOR_P (current_function_decl) without checking that c_f_d is non-null first. It seems correct that c_f_d is null here, so it seems to me that maybe_splice_retval_cleanup should check c_f_d as in the following patch.
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/12? PR c++/106925 gcc/cp/ChangeLog: * except.cc (maybe_splice_retval_cleanup): Check current_function_decl. gcc/testsuite/ChangeLog: * g++.dg/cpp0x/initlist-defarg3.C: New test. --- gcc/cp/except.cc | 3 +++ gcc/testsuite/g++.dg/cpp0x/initlist-defarg3.C | 13 +++++++++++++ 2 files changed, 16 insertions(+) create mode 100644 gcc/testsuite/g++.dg/cpp0x/initlist-defarg3.C diff --git a/gcc/cp/except.cc b/gcc/cp/except.cc index b8a85ed0572..9f77289b9ca 100644 --- a/gcc/cp/except.cc +++ b/gcc/cp/except.cc @@ -1327,6 +1327,9 @@ maybe_splice_retval_cleanup (tree compound_stmt) && current_binding_level->level_chain->kind == sk_function_parms);if ((function_body || current_binding_level->kind == sk_try)+ /* When we're processing a default argument, c_f_d may not have been + set. */ + && current_function_decl && !DECL_CONSTRUCTOR_P (current_function_decl) && !DECL_DESTRUCTOR_P (current_function_decl) && current_retval_sentinel) diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist-defarg3.C b/gcc/testsuite/g++.dg/cpp0x/initlist-defarg3.C new file mode 100644 index 00000000000..5c3e886b306 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/initlist-defarg3.C @@ -0,0 +1,13 @@ +// PR c++/106925 +// { dg-do compile { target c++11 } } + +struct Foo; +template <int _Nm> struct __array_traits { typedef Foo _Type[_Nm]; }; +template <int _Nm> struct array { + typename __array_traits<_Nm>::_Type _M_elems; +}; +template <int size> struct MyVector { array<size> data{}; }; +struct Foo { + float a{0}; +}; +void foo(MyVector<1> = MyVector<1>()); base-commit: 23c3cbaed36f6d2f3a7a64f6ebda69329723514b
