On 8/26/24 2:34 PM, Iain Sandoe wrote:
Hi Jason,
As the PR notes, we now have two bogus warnings that the single frame
pointer parameter is unused in each of the helper functions.
This started when we began to use start_preparsed_function/finish_function
to wrap the helper function code generation. I am puzzled a little about
why the use is not evident without marking - or perhaps it is always needed
to mark use in synthetic code?
For the destroy function, in particular, the use of the parameter is simple
- an indirect ref and then it is passed to the call to the actor.
The fix here is somewhat trivial - to mark the param as used as soon as it
is.
You also wouldn't get the warning if the param were marked DECL_ARTIFICIAL,
which seems desirable anyway?
Yes, done as attached, OK for trunk assuming that reg-testing passes?
OK.
--- 8< ---
We have a bogus warning about the coroutine state frame pointers
being apparently unused in the resume and destroy functions. Fixed
by making the parameters DECL_ARTIFICIAL.
PR c++/116482
gcc/cp/ChangeLog:
* coroutines.cc
(coro_build_actor_or_destroy_function): Make the parameter
decls DECL_ARTIFICIAL.
gcc/testsuite/ChangeLog:
* g++.dg/coroutines/pr116482.C: New test.
Signed-off-by: Iain Sandoe <i...@sandoe.co.uk>
---
gcc/cp/coroutines.cc | 1 +
gcc/testsuite/g++.dg/coroutines/pr116482.C | 30 ++++++++++++++++++++++
2 files changed, 31 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/coroutines/pr116482.C
diff --git a/gcc/cp/coroutines.cc b/gcc/cp/coroutines.cc
index c3e08221cc9..8f899513691 100644
--- a/gcc/cp/coroutines.cc
+++ b/gcc/cp/coroutines.cc
@@ -4058,6 +4058,7 @@ coro_build_actor_or_destroy_function (tree orig, tree
fn_type,
tree id = get_identifier ("frame_ptr");
tree fp = build_lang_decl (PARM_DECL, id, coro_frame_ptr);
+ DECL_ARTIFICIAL (fp) = true;
DECL_CONTEXT (fp) = fn;
DECL_ARG_TYPE (fp) = type_passed_as (coro_frame_ptr);
DECL_ARGUMENTS (fn) = fp;
diff --git a/gcc/testsuite/g++.dg/coroutines/pr116482.C
b/gcc/testsuite/g++.dg/coroutines/pr116482.C
new file mode 100644
index 00000000000..702d1e235bb
--- /dev/null
+++ b/gcc/testsuite/g++.dg/coroutines/pr116482.C
@@ -0,0 +1,30 @@
+// Override default options.
+// { dg-options "-std=c++20 -fno-exceptions -Wall -Wextra" }
+
+#include <coroutine>
+
+struct SuspendNever {
+ bool await_ready();
+ void await_suspend(std::coroutine_handle<>);
+ void await_resume();
+};
+
+struct Coroutine;
+
+struct PromiseType {
+ Coroutine get_return_object();
+ SuspendNever initial_suspend();
+ SuspendNever final_suspend();
+#if __cpp_exceptions
+ void unhandled_exception() { /*std::terminate();*/ };
+#endif
+ void return_void();
+};
+
+struct Coroutine {
+ using promise_type = PromiseType;
+};
+
+Coroutine __async_test_input_basic() {
+ co_return;
+}
