https://gcc.gnu.org/g:68da968e46e7603a4c11099a6c8dd5ad24e4f43e
commit r15-6701-g68da968e46e7603a4c11099a6c8dd5ad24e4f43e Author: Marek Polacek <pola...@redhat.com> Date: Tue Jan 7 10:15:42 2025 -0500 c++: ICE with MODIFY_EXPR in constexpr [PR118169] Here, cxx_eval_outermost_expression gets a sequence of initialization statements: D.2912.t = TARGET_EXPR <...>; TARGET_EXPR <D.2922, 1>; D.2922 = 0; the last of which wasn't converted to void and so we, since r15-6369, do not take the "if (VOID_TYPE_P (type))" path, and try to set D.2912 to false. The last statement comes from build_disable_temp_cleanup. convert_to_void is typically called from finish_expr_stmt, but we are adding the cleanup statement via add_stmt which doesn't convert to void. So I think we can use finish_expr_stmt instead. PR c++/118169 gcc/cp/ChangeLog: * typeck2.cc (split_nonconstant_init): Call finish_expr_stmt instead of add_stmt. gcc/testsuite/ChangeLog: * g++.dg/cpp1y/constexpr-prvalue2.C: New test. Reviewed-by: Jason Merrill <ja...@redhat.com> Diff: --- gcc/cp/typeck2.cc | 2 +- gcc/testsuite/g++.dg/cpp1y/constexpr-prvalue2.C | 13 +++++++++++++ 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/gcc/cp/typeck2.cc b/gcc/cp/typeck2.cc index 381f198d0fe6..5dae7fccf199 100644 --- a/gcc/cp/typeck2.cc +++ b/gcc/cp/typeck2.cc @@ -757,7 +757,7 @@ split_nonconstant_init (tree dest, tree init) init = NULL_TREE; for (tree f : flags) - add_stmt (build_disable_temp_cleanup (f)); + finish_expr_stmt (build_disable_temp_cleanup (f)); release_tree_vector (flags); code = pop_stmt_list (code); diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-prvalue2.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-prvalue2.C new file mode 100644 index 000000000000..7076c65b96ab --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-prvalue2.C @@ -0,0 +1,13 @@ +// PR c++/118169 +// { dg-do compile { target c++14 } } +// { dg-options "-O" } + +struct A { constexpr A (int *x) : s(x) {} ~A (); int *s; }; +struct B { A t; int u = 0; }; +void foo (B &&); + +void +bar (int &x) +{ + foo ({ &x }); +}