From be20dcc359bcc4677c5b9ce011d3cd7b4ce94a64 Mon Sep 17 00:00:00 2001 From: Marek Polacek Date: Fri, 10 Mar 2023 10:14:20 -0500 Subject: [PATCH] c++: ICE with constexpr lambda [PR107280] We crash here since r10-3661, the store_init_value hunk in particular. Before, we called cp_fully_fold_init, so e.g. {.str=VIEW_CONVERT_EXPR("")} was folded into {.str=""} but now we don't fold and keep the VCE around, and it causes trouble in cxx_eval_store_expression: in the !refs->is_empty () loop we descend on .str's initializer but since it's wrapped in a VCE, we skip the STRING_CST check and then crash on the CONSTRUCTOR_NO_CLEARING. PR c++/107280 gcc/cp/ChangeLog: * constexpr.cc (cxx_eval_store_expression): Strip location wrappers. gcc/testsuite/ChangeLog: * g++.dg/cpp1z/constexpr-lambda28.C: New test. --- gcc/cp/constexpr.cc | 3 ++- gcc/testsuite/g++.dg/cpp1z/constexpr-lambda28.C | 15 +++++++++++++++ 2 files changed, 17 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/cpp1z/constexpr-lambda28.C diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc index 8683c00..abf6ee5 100644 --- a/gcc/cp/constexpr.cc +++ b/gcc/cp/constexpr.cc @@ -6033,7 +6033,8 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, *valp = build_constructor (type, NULL); CONSTRUCTOR_NO_CLEARING (*valp) = no_zero_init; } - else if (TREE_CODE (*valp) == STRING_CST) + else if (STRIP_ANY_LOCATION_WRAPPER (*valp), + TREE_CODE (*valp) == STRING_CST) { /* An array was initialized with a string constant, and now we're writing into one of its elements. Explode the diff --git a/gcc/testsuite/g++.dg/cpp1z/constexpr-lambda28.C b/gcc/testsuite/g++.dg/cpp1z/constexpr-lambda28.C new file mode 100644 index 0000000..aafbfdd --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1z/constexpr-lambda28.C @@ -0,0 +1,15 @@ +// PR c++/107280 +// { dg-do compile { target c++17 } } + +struct string { + char str[8] = ""; +}; +template constexpr void +test () +{ + string str{}; + auto append = [&](const char *s) { *str.str = *s; }; + append(""); +} + +static_assert ((test(), true), ""); -- 2.7.4