Hi, On 11 Dec 2024, at 22:27, Simon Martin wrote:
> Hi, > > On 29 Nov 2024, at 15:33, Simon Martin wrote: > >> We currently ICE upon the following code, that is valid under >> -Wno-pointer-arith: >> >> === cut here === >> int main() { >> decltype( [](auto) { return sizeof(void); } ) x; >> return x.operator()(0); >> } >> === cut here === >> >> The problem is that "fold_sizeof_expr (sizeof(void))" returns >> size_one_node, that has a different TREE_TYPE from that of the sizeof >> expression, which later triggers an assert in >> cxx_eval_store_expression. >> >> This patch makes sure that fold_sizeof_expr always returns a tree with >> the type requested. >> >> Successfully tested on x86_64-pc-linux-gnu. > Ping. Ping. Thanks! Simon >> >> PR c++/117775 >> >> gcc/cp/ChangeLog: >> >> * decl.cc (fold_sizeof_expr): Make sure the folded result has >> the requested TREE_TYPE. >> >> gcc/testsuite/ChangeLog: >> >> * g++.dg/cpp2a/constexpr-117775.C: New test. >> >> --- >> gcc/cp/decl.cc | 1 + >> gcc/testsuite/g++.dg/cpp2a/constexpr-117775.C | 13 +++++++++++++ >> 2 files changed, 14 insertions(+) >> create mode 100644 gcc/testsuite/g++.dg/cpp2a/constexpr-117775.C >> >> diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc >> index 80485f0a428..fbe1407a2d2 100644 >> --- a/gcc/cp/decl.cc >> +++ b/gcc/cp/decl.cc >> @@ -11686,6 +11686,7 @@ fold_sizeof_expr (tree t) >> false, false); >> if (r == error_mark_node) >> r = size_one_node; >> + r = cp_fold_convert (TREE_TYPE (t), r); >> return r; >> } >> >> diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-117775.C >> b/gcc/testsuite/g++.dg/cpp2a/constexpr-117775.C >> new file mode 100644 >> index 00000000000..59fc0d332b9 >> --- /dev/null >> +++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-117775.C >> @@ -0,0 +1,13 @@ >> +// PR c++/117775 >> +// Check that we don't ICE and have sizeof(void)==1 under >> -Wno-pointer-arith >> +// { dg-do run { target c++20 } } >> +// { dg-additional-options "-Wno-pointer-arith" } >> + >> +int main() { >> + struct why : >> + decltype( [](auto) { >> + return sizeof(void); >> + }) >> + {} x; >> + return 1 - x.operator()(0); >> +} >> -- >> 2.44.0