| Message ID | 20230310161713.124368-1-polacek@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | c++: ICE with constexpr lambda [PR107280] | expand |
On 3/10/23 11:17, Marek Polacek wrote: > 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<char[8]>("")} > > 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. > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/12? > > 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 8683c00596a..abf6ee560c5 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) Seems like this is stripping the location wrapper when we try to modify the string; I think we want to strip it earlier, when we first initialize the array member. Jason
diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc index 8683c00596a..abf6ee560c5 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 00000000000..aafbfddd8b9 --- /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 <int, int> constexpr void +test () +{ + string str{}; + auto append = [&](const char *s) { *str.str = *s; }; + append(""); +} + +static_assert ((test<true, true>(), true), "");
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<char[8]>("")} 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. Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/12? 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 base-commit: 2b2340e236c0bba8aaca358ea25a5accd8249fbd