Tested on x86_64-pc-linux-gnu, does this look OK for trunk/14?
-- >8 --
In r15-2210 we got rid of the unnecessary cast to lvalue reference when
passing *this to the promise type ctor, and as a drive-by change we also
simplified the code to use cp_build_fold_indirect_ref.
But cp_build_fold_indirect_ref apparently does too much here, namely
it has a shortcut for returning current_class_ref if the operand is
current_class_ptr. The problem with that shortcut is current_class_ref
might have gotten clobbered earlier if it appeared in the function body,
since rewrite_param_uses walks and rewrites in-place all local variable
uses to their corresponding frame copy.
So later this cp_build_fold_indirect_ref for *__closure will instead return
the mutated current_class_ref i.e. *frame_ptr->__closure, which doesn't
make sense here since we're in the ramp function and not the actor function
where frame_ptr is in scope.
This patch fixes this by building INDIRECT_REF directly instead of using
cp_build_fold_indirect_ref. (Another approach might be to restore an
unshare_expr'd current_class_ref after doing coro_rewrite_function_body
to avoid it remaining clobbered after the rewriting process. Yet
another more ambitious approach might be to avoid this tree sharing in
the first place by returning unshared versions of current_class_ref from
maybe_dummy_object etc.)
PR c++/116327
PR c++/104981
PR c++/115550
gcc/cp/ChangeLog:
* coroutines.cc (morph_fn_to_coro): Build INDIRECT_REF directly
instead of using cp_build_fold_indirect_ref when doing *this.
gcc/testsuite/ChangeLog:
* g++.dg/coroutines/pr116327-preview-this.C: New test.
---
gcc/cp/coroutines.cc | 6 +++--
.../g++.dg/coroutines/pr116327-preview-this.C | 22 +++++++++++++++++++
2 files changed, 26 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/coroutines/pr116327-preview-this.C
diff --git a/gcc/cp/coroutines.cc b/gcc/cp/coroutines.cc
index 145ec4b1d16..58be456ce00 100644
--- a/gcc/cp/coroutines.cc
+++ b/gcc/cp/coroutines.cc
@@ -4850,7 +4850,8 @@ morph_fn_to_coro (tree orig, tree *resumer, tree
*destroyer)
if (parm_i->this_ptr || parm_i->lambda_cobj)
{
/* We pass a reference to *this to the allocator lookup. */
- tree this_ref = cp_build_fold_indirect_ref (arg);
+ tree tt = TREE_TYPE (TREE_TYPE (arg));
+ tree this_ref = build1 (INDIRECT_REF, tt, arg);
vec_safe_push (args, this_ref);
}
else
@@ -5070,7 +5071,8 @@ morph_fn_to_coro (tree orig, tree *resumer, tree
*destroyer)
if (parm.this_ptr || parm.lambda_cobj)
{
/* We pass a reference to *this to the param preview. */
- tree this_ref = cp_build_fold_indirect_ref (arg);
+ tree tt = TREE_TYPE (TREE_TYPE (arg));
+ tree this_ref = build1 (INDIRECT_REF, tt, arg);
vec_safe_push (promise_args, this_ref);
}
else if (parm.rv_ref)
diff --git a/gcc/testsuite/g++.dg/coroutines/pr116327-preview-this.C
b/gcc/testsuite/g++.dg/coroutines/pr116327-preview-this.C
new file mode 100644
index 00000000000..27b69a41392
--- /dev/null
+++ b/gcc/testsuite/g++.dg/coroutines/pr116327-preview-this.C
@@ -0,0 +1,22 @@
+// PR c++/116327 - ICE in coroutine with parameter preview on lambda with
captures
+
+#include <coroutine>
+
+struct coroutine{
+ struct promise_type{
+ promise_type(const auto &...){}
+ std::suspend_never initial_suspend(){ return {}; }
+ std::suspend_always final_suspend()noexcept{ return {}; }
+ void unhandled_exception(){}
+ coroutine get_return_object(){ return {}; }
+ void return_value(int)noexcept{}
+ };
+};
+
+int main(){
+ auto f = [a=0](auto) -> coroutine {
+ co_return 2;
+ };
+ f(0);
+ return 0;
+}
--
2.46.0.77.g25673b1c47
