c++/coroutines: fix passing *this to promise type, again [PR116327]

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 it turns out cp_build_fold_indirect_ref 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 cp_build_fold_indirect_ref for *this will instead return the
clobbered current_class_ref i.e. *frame_ptr->this, 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 using the build_fold_indirect_ref instead of
cp_build_fold_indirect_ref.

	PR c++/116327
	PR c++/104981
	PR c++/115550

gcc/cp/ChangeLog:

	* coroutines.cc (morph_fn_to_coro): Use build_fold_indirect_ref
	instead of cp_build_fold_indirect_ref.

gcc/testsuite/ChangeLog:

	* g++.dg/coroutines/pr104981-preview-this.C: Improve coverage by
	adding a non-static data member use within the coroutine member
	function.
	* g++.dg/coroutines/pr116327-preview-this.C: New test.

Reviewed-by: Jason Merrill <jason@redhat.com>

0 files changed, 0 insertions, 0 deletions