When make_base_init_ok changes a call to a complete constructor into a call to a base constructor, we were never marking the base ctor as used, so it didn't get emitted.
Tested x86_64-pc-linux-gnu, applying to trunk. PR c++/102045 gcc/cp/ChangeLog: * call.cc (make_base_init_ok): Call make_used. gcc/testsuite/ChangeLog: * g++.dg/cpp1z/aggr-base12.C: New test. --- gcc/cp/call.cc | 1 + gcc/testsuite/g++.dg/cpp1z/aggr-base12.C | 24 ++++++++++++++++++++++++ 2 files changed, 25 insertions(+) create mode 100644 gcc/testsuite/g++.dg/cpp1z/aggr-base12.C diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc index dfe370d685d..73fede5a3df 100644 --- a/gcc/cp/call.cc +++ b/gcc/cp/call.cc @@ -8958,6 +8958,7 @@ make_base_init_ok (tree exp) call target. It would be possible to splice in the appropriate arguments, but probably not worth the complexity. */ return false; + mark_used (fn); AGGR_INIT_EXPR_FN (exp) = build_address (fn); return true; } diff --git a/gcc/testsuite/g++.dg/cpp1z/aggr-base12.C b/gcc/testsuite/g++.dg/cpp1z/aggr-base12.C new file mode 100644 index 00000000000..6f5a6b2056a --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1z/aggr-base12.C @@ -0,0 +1,24 @@ +// PR c++/102045 +// { dg-do link { target c++17 } } + +template<typename T> +struct span +{ + template<unsigned long N> + constexpr span(T (&a)[N]) : data(a), len(N) { } + constexpr bool empty() const { return len == 0; } + T* data; + unsigned long len; +}; + +struct byte_writer: span<char> { + constexpr void do_something() noexcept { + (void)this->empty(); + } +}; + +int main() { + char array[1]; + auto writer = byte_writer{array}; + writer.do_something(); +} base-commit: bc86a86a4f2c057bc0e0be94dcbb8c128ae7f717 prerequisite-patch-id: 09e711b54e7911a4a04bd7808abc1b73ae4482ba prerequisite-patch-id: 566cf0772894d0c6a842b2e0ca62eb1d5ae8ad33 prerequisite-patch-id: b1def7e83e76c1652efb483cb2b67e472d15b720 -- 2.27.0