First constinit bug report (yay?). The problem is that while I made sure
that constinit variable templates work as they should, I clearly neglected
ordinary static variables declared constinit in function templates.
This was an ICE in cp_finish_decl when setting TINFO_VAR_DECLARED_CONSTINIT
because 'v' here
template <typename T>
static void f ()
{
static constinit int v = 42;
}
didn't have DECL_TEMPLATE_INFO allocated. Fixed by using retrofit_lang_decl
so that push_template_decl then saves the DECL_TEMPLATE_INFO it creates:
5821 info = build_template_info (tmpl, args);
...
5829 if (DECL_LANG_SPECIFIC (decl))
5830 DECL_TEMPLATE_INFO (decl) = info;
And then we need to make sure that tsubst_expr actually uses the T_V_D_C flag.
As an aside, I'm concerned that if we're required to handle
// Foo.h
struct Foo {
constinit static int x;
};
// Foo.cpp
int Foo::x = 42;
we might need to resurrect DECL_DECLARED_CONSTINIT_P...
Bootstrapped/regtested on x86_64-linux, ok for trunk?
2019-09-03 Marek Polacek <[email protected]>
PR c++/91644 - ICE with constinit in function template.
* decl.c (start_decl): Call retrofit_lang_decl for constinit variables.
* pt.c (tsubst_expr): Pass LOOKUP_CONSTINIT down to cp_finish_decl for
constinit variables.
* g++.dg/cpp2a/constinit13.C: New test.
diff --git gcc/cp/decl.c gcc/cp/decl.c
index 6de95cdfe79..825e1e61b5e 100644
--- gcc/cp/decl.c
+++ gcc/cp/decl.c
@@ -5308,7 +5308,14 @@ start_decl (const cp_declarator *declarator,
decl = maybe_push_decl (decl);
if (processing_template_decl)
- decl = push_template_decl (decl);
+ {
+ /* Make sure that for a `constinit' decl push_template_decl creates
+ a DECL_TEMPLATE_INFO info for us, so that cp_finish_decl can then set
+ TINFO_VAR_DECLARED_CONSTINIT. */
+ if (decl_spec_seq_has_spec_p (declspecs, ds_constinit))
+ retrofit_lang_decl (decl);
+ decl = push_template_decl (decl);
+ }
if (decl == error_mark_node)
return error_mark_node;
diff --git gcc/cp/pt.c gcc/cp/pt.c
index 187f9d857bc..3e6a2000780 100644
--- gcc/cp/pt.c
+++ gcc/cp/pt.c
@@ -17108,6 +17108,13 @@ tsubst_expr (tree t, tree args, tsubst_flags_t
complain, tree in_decl,
else
{
init = DECL_INITIAL (decl);
+ /* The following tsubst call will clear the DECL_TEMPLATE_INFO
+ for local variables, so save if DECL was declared constinit. */
+ const bool constinit_p
+ = (VAR_P (decl)
+ && DECL_LANG_SPECIFIC (decl)
+ && DECL_TEMPLATE_INFO (decl)
+ && TINFO_VAR_DECLARED_CONSTINIT (DECL_TEMPLATE_INFO (decl)));
decl = tsubst (decl, args, complain, in_decl);
if (decl != error_mark_node)
{
@@ -17146,7 +17153,7 @@ tsubst_expr (tree t, tree args, tsubst_flags_t
complain, tree in_decl,
}
else
{
- int const_init = false;
+ bool const_init = false;
unsigned int cnt = 0;
tree first = NULL_TREE, ndecl = error_mark_node;
maybe_push_decl (decl);
@@ -17167,7 +17174,8 @@ tsubst_expr (tree t, tree args, tsubst_flags_t
complain, tree in_decl,
if (ndecl != error_mark_node)
cp_maybe_mangle_decomp (ndecl, first, cnt);
- cp_finish_decl (decl, init, const_init, NULL_TREE, 0);
+ cp_finish_decl (decl, init, const_init, NULL_TREE,
+ constinit_p ? LOOKUP_CONSTINIT : 0);
if (ndecl != error_mark_node)
cp_finish_decomp (ndecl, first, cnt);
diff --git gcc/testsuite/g++.dg/cpp2a/constinit13.C
gcc/testsuite/g++.dg/cpp2a/constinit13.C
new file mode 100644
index 00000000000..8ea64cc0e1e
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp2a/constinit13.C
@@ -0,0 +1,33 @@
+// PR c++/91644 - ICE with constinit in function template.
+// { dg-do compile { target c++11 } }
+
+template <typename T>
+static void fn1 ()
+{
+ static __constinit auto v1 = 0;
+ static __constinit int v2 = 0;
+}
+
+int nonconst;
+
+template <typename T>
+static void fn2 ()
+{
+ static __constinit auto v1 = nonconst; // { dg-error "does not have a
constant initializer|not usable" }
+ static __constinit int v2 = nonconst; // { dg-error "does not have a
constant initializer|not usable" }
+}
+
+template <typename T>
+static void fn3 ()
+{
+ static __constinit T v1 = 0;
+ static __constinit T v2 = nonconst; // { dg-error "does not have a constant
initializer|not usable" }
+}
+
+void
+g ()
+{
+ fn1<int>();
+ fn2<int>();
+ fn3<int>();
+}
