| Message ID | 20231023234924.2971461-1-ppalka@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | c++: cp_stabilize_reference and non-dep exprs [PR111919] | expand |
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; > +}
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; +}