We already suppress various warnings for code that would be tautological if written directly, but not when it's the result of template substitution. It seems we need to do this for -Waddress as well.
Tested x86_64-pc-linux-gnu, applying to trunk. PR c++/105885 gcc/cp/ChangeLog: * pt.cc (tsubst_copy_and_build): Also suppress -Waddress for comparison of dependent operands. gcc/testsuite/ChangeLog: * g++.dg/cpp1z/constexpr-if37.C: New test. --- gcc/cp/pt.cc | 1 + gcc/testsuite/g++.dg/cpp1z/constexpr-if37.C | 21 +++++++++++++++++++++ 2 files changed, 22 insertions(+) create mode 100644 gcc/testsuite/g++.dg/cpp1z/constexpr-if37.C diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index 80d2bec2348..4535c14c26a 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -20438,6 +20438,7 @@ tsubst_copy_and_build (tree t, warning_sentinel s2(warn_div_by_zero, was_dep); warning_sentinel s3(warn_logical_op, was_dep); warning_sentinel s4(warn_tautological_compare, was_dep); + warning_sentinel s5(warn_address, was_dep); tree r = build_x_binary_op (input_location, TREE_CODE (t), diff --git a/gcc/testsuite/g++.dg/cpp1z/constexpr-if37.C b/gcc/testsuite/g++.dg/cpp1z/constexpr-if37.C new file mode 100644 index 00000000000..e11e02cfa0e --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1z/constexpr-if37.C @@ -0,0 +1,21 @@ +// PR c++/105885 +// { dg-do compile { target c++17 } } +// { dg-additional-options -Wall } + +int i; + +template<const char* ARG = nullptr> +void test() { + if constexpr(ARG == nullptr) { + ++i; + } else { + --i; + } +} + +const char CONSTSTR[] = {'\n', '\t', ' ', '\0'}; + +int main() { + test(); + test<CONSTSTR>(); +} base-commit: 8a15cd3396aa08dc2633982481fe392af0aa9e78 -- 2.27.0