Bootstrapped and regtested on x86_64-pc-linux-gnu, OK for trunk?
-- >8 --
Currently the streaming code uses TREE_CONSTANT to determine whether an
entity will have a definition that is interesting to stream out. This
is not sufficient, however; we also need to write the definition of
references, since although not TREE_CONSTANT they can still be usable in
constant expressions.
gcc/cp/ChangeLog:
* module.cc (has_definition): Also write definition of
references initialized with a constant expression.
gcc/testsuite/ChangeLog:
* g++.dg/modules/cexpr-5_a.C: New test.
* g++.dg/modules/cexpr-5_b.C: New test.
Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com>
---
gcc/cp/module.cc | 6 +++++-
gcc/testsuite/g++.dg/modules/cexpr-5_a.C | 13 +++++++++++++
gcc/testsuite/g++.dg/modules/cexpr-5_b.C | 9 +++++++++
3 files changed, 27 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/modules/cexpr-5_a.C
create mode 100644 gcc/testsuite/g++.dg/modules/cexpr-5_b.C
diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index f5df9e875d3..7589de2348d 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -11829,7 +11829,11 @@ has_definition (tree decl)
since there's no TU to emit them in otherwise. */
return true;
- if (!TREE_CONSTANT (decl))
+ if (!TREE_CONSTANT (decl)
+ /* A reference is never TREE_CONSTANT, but still stream its
+ definition if it's usable in constant expressions. */
+ && !(TYPE_REF_P (TREE_TYPE (decl))
+ && DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (decl)))
return false;
return true;
diff --git a/gcc/testsuite/g++.dg/modules/cexpr-5_a.C
b/gcc/testsuite/g++.dg/modules/cexpr-5_a.C
new file mode 100644
index 00000000000..3a9f00523f6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/cexpr-5_a.C
@@ -0,0 +1,13 @@
+// { dg-additional-options "-fmodules-ts" }
+// { dg-module-cmi M }
+
+export module M;
+
+int x = 123;
+void f() {}
+
+int& xr = x;
+auto& fr = f;
+
+constexpr int& cxr = xr;
+constexpr auto& cfr = fr;
diff --git a/gcc/testsuite/g++.dg/modules/cexpr-5_b.C
b/gcc/testsuite/g++.dg/modules/cexpr-5_b.C
new file mode 100644
index 00000000000..4b1b901104b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/cexpr-5_b.C
@@ -0,0 +1,9 @@
+// { dg-additional-options "-fmodules-ts" }
+
+module M;
+
+constexpr auto& use_xr = xr;
+constexpr auto& use_fr = fr;
+
+static_assert(&cxr == &use_xr);
+static_assert(&cfr == &use_fr);
--
2.46.0
