On 6/29/23 11:36, Marek Polacek wrote:
On Thu, Jun 29, 2023 at 11:22:55AM -0400, Patrick Palka via Gcc-patches wrote:
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
trunk/13?
-- >8 --
cp_fold is neglecting to propagate CONSTRUCTOR_MUTABLE_POISON when folding
a CONSTRUCTOR initializer, which for the below testcase causes us to fail
to reject a mutable member access of a constexpr variable during constexpr
evaluation.
LGTM.
Agreed, OK.
PR c++/110463
gcc/cp/ChangeLog:
* cp-gimplify.cc (cp_fold) <case CONSTRUCTOR>: Propagate
CONSTRUCTOR_MUTABLE_POISON.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/constexpr-mutable6.C: New test.
---
gcc/cp/cp-gimplify.cc | 2 ++
.../g++.dg/cpp0x/constexpr-mutable6.C | 18 ++++++++++++++++++
2 files changed, 20 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/constexpr-mutable6.C
diff --git a/gcc/cp/cp-gimplify.cc b/gcc/cp/cp-gimplify.cc
index 853b1e44236..f5734197774 100644
--- a/gcc/cp/cp-gimplify.cc
+++ b/gcc/cp/cp-gimplify.cc
@@ -3079,6 +3079,8 @@ cp_fold (tree x, fold_flags_t flags)
x = build_constructor (TREE_TYPE (x), nelts);
CONSTRUCTOR_PLACEHOLDER_BOUNDARY (x)
= CONSTRUCTOR_PLACEHOLDER_BOUNDARY (org_x);
+ CONSTRUCTOR_MUTABLE_POISON (x)
+ = CONSTRUCTOR_MUTABLE_POISON (org_x);
}
if (VECTOR_TYPE_P (TREE_TYPE (x)))
x = fold (x);
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-mutable6.C
b/gcc/testsuite/g++.dg/cpp0x/constexpr-mutable6.C
new file mode 100644
index 00000000000..2c946e388ab
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-mutable6.C
@@ -0,0 +1,18 @@
+// PR c++/110463
+// { dg-do compile { target c++11 } }
+
+struct U {
+ mutable int x = 1;
+};
+
+struct V {
+ mutable int y = 1+1;
+};
+
+int main() {
+ constexpr U u = {};
+ constexpr int x = u.x; // { dg-error "mutable" }
+
+ constexpr V v = {};
+ constexpr int y = v.y; // { dg-error "mutable" }
+}
--
2.41.0.199.ga9e066fa63
Marek
