From 51f164f76212feaf896d65616f60877d3217b701 Mon Sep 17 00:00:00 2001
From: Patrick Palka <ppalka@redhat.com>
Date: Tue, 24 Oct 2023 17:48:00 -0400
Subject: [PATCH] c++: cp_stabilize_reference and non-dep exprs [PR111919]
After the removal of NON_DEPENDENT_EXPR, cp_stabilize_reference (which
used to just exit early for NON_DEPENDENT_EXPR) is now more prone to
passing a weird templated tree to middle-end routines, which for the
testcase below leads to a crash from contains_placeholder_p. It seems
the best fix is to just exit early when in a template context, like we
do in the closely related function cp_save_expr.
PR c++/111919
gcc/cp/ChangeLog:
* tree.cc (cp_stabilize_reference): Do nothing when
processing_template_decl.
gcc/testsuite/ChangeLog:
* g++.dg/template/non-dependent27.C: New test.
---
gcc/cp/tree.cc | 4 ++++
gcc/testsuite/g++.dg/template/non-dependent27.C | 8 ++++++++
2 files changed, 12 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/template/non-dependent27.C
diff --git a/gcc/cp/tree.cc b/gcc/cp/tree.cc
index a3d61d3e7c98..417c92ba76fc 100644
--- a/gcc/cp/tree.cc
+++ b/gcc/cp/tree.cc
@@ -408,6 +408,10 @@ bitfield_p (const_tree ref)
tree
cp_stabilize_reference (tree ref)
{
+ if (processing_template_decl)
+ /* As in cp_save_expr. */
+ return ref;
+
STRIP_ANY_LOCATION_WRAPPER (ref);
switch (TREE_CODE (ref))
{
diff --git a/gcc/testsuite/g++.dg/template/non-dependent27.C b/gcc/testsuite/g++.dg/template/non-dependent27.C
new file mode 100644
index 000000000000..c06bca73d64f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/non-dependent27.C
@@ -0,0 +1,8 @@
+// PR c++/111919
+
+int i[42];
+
+template<class T>
+void f() {
+ i[42 / (int)sizeof(T)] |= 42;
+}
--
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