On 10/23/23 19:49, Patrick Palka wrote:
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK
for trunk?
-- >8 --
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 leads to a
crash from contains_placeholder_p in the testcase below. It seems the
best fix is to just disable cp_stabilize_reference when in a template
context like we already do for cp_save_expr; it seems SAVE_EXPR should
never appear in a templated tree (since e.g. tsubst doesn't handle it).
Hmm. We don't want the result of cp_stabilize_reference (or
cp_save_expr) to end up in the resulting trees in template context.
Having a SAVE_EXPR in the result would actually be helpful for catching
such a bug.
That said, the patch is OK.
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 a3d61d3e7c9..417c92ba76f 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 00000000000..cf7af6e6425
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/non-dependent27.C
@@ -0,0 +1,8 @@
+// PR c++/111919
+
+int i[3];
+
+template<class T>
+void f() {
+ i[42 / (int) sizeof (T)] |= 0;
+}
