[gcc r13-6697] c++: ICE with constexpr lambda [PR107280]
Marek Polacek
mpolacek@gcc.gnu.org
Wed Mar 15 18:28:24 GMT 2023
https://gcc.gnu.org/g:be20dcc359bcc4677c5b9ce011d3cd7b4ce94a64
commit r13-6697-gbe20dcc359bcc4677c5b9ce011d3cd7b4ce94a64
Author: Marek Polacek <polacek@redhat.com>
Date: Fri Mar 10 10:14:20 2023 -0500
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<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.
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.
Diff:
---
gcc/cp/constexpr.cc | 3 ++-
gcc/testsuite/g++.dg/cpp1z/constexpr-lambda28.C | 15 +++++++++++++++
2 files changed, 17 insertions(+), 1 deletion(-)
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), "");
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