diff mbox series

[3/9,v3] c++, coroutines: Separate allocator work from the ramp body build.

Message ID 20240823134112.20280-1-iain@sandoe.co.uk
State New
Headers show
Series None | expand

Commit Message

Iain Sandoe Aug. 23, 2024, 1:41 p.m. UTC
>>>http://eel.is/c++draft/dcl.fct.def.coroutine#12 (sentence 2) says " If both a usual deallocation function with only a pointer parameter and a usual deallocation function with both a pointer parameter and a size parameter are found, then the selected deallocation function shall be the one with two parameters.”
>>>however, if my promise provides both - the one with a single param is always chosen.
>>>It is not that the other overload is invalid - if I do not include the single param version, the two param one is happily selected.

>>Ah, that's backwards from https://eel.is/c++draft/expr.delete#9.4 "If the deallocation functions belong to a class scope, the one without a parameter of type std​::​size_t is selected."
>>
>>This is implemented as
>>
>>          /* -- If the deallocation functions have class scope, the one without a parameter of type std::size_t is selected.  */
>>          bool want_size;
>>          if (DECL_CLASS_SCOPE_P (fn))
>>            want_size = false;
>>
>>I guess we need some way for build_op_delete_call to know that we want the other preference in this case.

>Adding a defaulted param to the existing call seems to be messy since it would interrupt the complain being last parm theme..

>… I suppose we could add an overload with an additional bool specifying priority to the two argument case?

>if that seems reasonable, I can take that on - as part of this patch (or separately).

That patch might look as below.

I have addressed the other comments here;

If this does not look like a good direction, then perhaps we could proceed
with the original version and address improvements as a follow-on along with
the other changes we need to make to support over-aligned frame objects?

thanks,
Iain

--- 8< ---

This splits out the building of the allocation and deallocation expressions
and runs them early in the ramp build, so that we can exit if they are not
usable, before we start building the ramp body.

Likewise move checks for other required resources to the begining of the
ramp builder.

This is preparation for work needed to update the allocation/destruction
in cases where we have excess alignment of the promise or other saved frame
state.

gcc/cp/ChangeLog:

	* call.cc (build_op_delete_call_1): Renamed and added a param
	to allow the caller to prioritize two argument usual deleters.
	(build_op_delete_call): Add an overload to expose the option
	to prioritize two argument deleters.
	* coroutines.cc (coro_get_frame_dtor): Rename...
	(build_coroutine_frame_delete_expr):... to this; simplify to
	use build_op_delete_call for all cases.
	(build_actor_fn): Use revised frame delete function.
	(build_coroutine_frame_alloc_expr): New.
	(cp_coroutine_transform::complete_ramp_function): Rename...
	(cp_coroutine_transform::build_ramp_function): ... to this.
	Reorder code to carry out checks for prerequisites before the
	codegen. Split out the allocation/delete code.
	(cp_coroutine_transform::apply_transforms): Use revised name.
	* coroutines.h: Rename function.
	* cp-tree.h (build_op_delete_call): Add an overload for the version
	that allows two operand deleters.

gcc/testsuite/ChangeLog:

	* g++.dg/coroutines/coro-bad-alloc-01-bad-op-del.C: Use revised
	diagnostics.
	* g++.dg/coroutines/coro-bad-gro-00-class-gro-scalar-return.C:
	Likewise.
	* g++.dg/coroutines/coro-bad-gro-01-void-gro-non-class-coro.C:
	Likewise.
	* g++.dg/coroutines/coro-bad-grooaf-00-static.C: Likewise.
	* g++.dg/coroutines/ramp-return-b.C: Likewise.

Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>
---
 gcc/cp/call.cc                                |  36 +-
 gcc/cp/coroutines.cc                          | 462 ++++++++++--------
 gcc/cp/coroutines.h                           |   2 +-
 gcc/cp/cp-tree.h                              |   3 +
 .../coroutines/coro-bad-alloc-01-bad-op-del.C |   2 +-
 .../coro-bad-gro-00-class-gro-scalar-return.C |   4 +-
 .../coro-bad-gro-01-void-gro-non-class-coro.C |   4 +-
 .../coroutines/coro-bad-grooaf-00-static.C    |   6 +-
 .../g++.dg/coroutines/ramp-return-b.C         |   8 +-
 9 files changed, 292 insertions(+), 235 deletions(-)

Comments

Jason Merrill Aug. 24, 2024, 3:08 a.m. UTC | #1
On 8/23/24 9:41 AM, Iain Sandoe wrote:
>>>> http://eel.is/c++draft/dcl.fct.def.coroutine#12 (sentence 2) says " If both a usual deallocation function with only a pointer parameter and a usual deallocation function with both a pointer parameter and a size parameter are found, then the selected deallocation function shall be the one with two parameters.”
>>>> however, if my promise provides both - the one with a single param is always chosen.
>>>> It is not that the other overload is invalid - if I do not include the single param version, the two param one is happily selected.
> 
>>> Ah, that's backwards from https://eel.is/c++draft/expr.delete#9.4 "If the deallocation functions belong to a class scope, the one without a parameter of type std​::​size_t is selected."
>>>
>>> This is implemented as
>>>
>>>           /* -- If the deallocation functions have class scope, the one without a parameter of type std::size_t is selected.  */
>>>           bool want_size;
>>>           if (DECL_CLASS_SCOPE_P (fn))
>>>             want_size = false;
>>>
>>> I guess we need some way for build_op_delete_call to know that we want the other preference in this case.
> 
>> Adding a defaulted param to the existing call seems to be messy since it would interrupt the complain being last parm theme..
> 
>> … I suppose we could add an overload with an additional bool specifying priority to the two argument case?
> 
>> if that seems reasonable, I can take that on - as part of this patch (or separately).
> 
> That patch might look as below.
> 
> I have addressed the other comments here;
> 
> If this does not look like a good direction, then perhaps we could proceed
> with the original version and address improvements as a follow-on along with
> the other changes we need to make to support over-aligned frame objects?
> 
> thanks,
> Iain
> 
> --- 8< ---
> 
> This splits out the building of the allocation and deallocation expressions
> and runs them early in the ramp build, so that we can exit if they are not
> usable, before we start building the ramp body.
> 
> Likewise move checks for other required resources to the begining of the
> ramp builder.
> 
> This is preparation for work needed to update the allocation/destruction
> in cases where we have excess alignment of the promise or other saved frame
> state.
> 
> gcc/cp/ChangeLog:
> 
> 	* call.cc (build_op_delete_call_1): Renamed and added a param
> 	to allow the caller to prioritize two argument usual deleters.
> 	(build_op_delete_call): Add an overload to expose the option
> 	to prioritize two argument deleters.
> 	* coroutines.cc (coro_get_frame_dtor): Rename...
> 	(build_coroutine_frame_delete_expr):... to this; simplify to
> 	use build_op_delete_call for all cases.
> 	(build_actor_fn): Use revised frame delete function.
> 	(build_coroutine_frame_alloc_expr): New.
> 	(cp_coroutine_transform::complete_ramp_function): Rename...
> 	(cp_coroutine_transform::build_ramp_function): ... to this.
> 	Reorder code to carry out checks for prerequisites before the
> 	codegen. Split out the allocation/delete code.
> 	(cp_coroutine_transform::apply_transforms): Use revised name.
> 	* coroutines.h: Rename function.
> 	* cp-tree.h (build_op_delete_call): Add an overload for the version
> 	that allows two operand deleters.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/coroutines/coro-bad-alloc-01-bad-op-del.C: Use revised
> 	diagnostics.
> 	* g++.dg/coroutines/coro-bad-gro-00-class-gro-scalar-return.C:
> 	Likewise.
> 	* g++.dg/coroutines/coro-bad-gro-01-void-gro-non-class-coro.C:
> 	Likewise.
> 	* g++.dg/coroutines/coro-bad-grooaf-00-static.C: Likewise.
> 	* g++.dg/coroutines/ramp-return-b.C: Likewise.
> 
> Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>
> ---
>   gcc/cp/call.cc                                |  36 +-
>   gcc/cp/coroutines.cc                          | 462 ++++++++++--------
>   gcc/cp/coroutines.h                           |   2 +-
>   gcc/cp/cp-tree.h                              |   3 +
>   .../coroutines/coro-bad-alloc-01-bad-op-del.C |   2 +-
>   .../coro-bad-gro-00-class-gro-scalar-return.C |   4 +-
>   .../coro-bad-gro-01-void-gro-non-class-coro.C |   4 +-
>   .../coroutines/coro-bad-grooaf-00-static.C    |   6 +-
>   .../g++.dg/coroutines/ramp-return-b.C         |   8 +-
>   9 files changed, 292 insertions(+), 235 deletions(-)
> 
> diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc
> index 0fe679aae9f..377882a1c61 100644
> --- a/gcc/cp/call.cc
> +++ b/gcc/cp/call.cc
> @@ -7851,6 +7851,8 @@ usual_deallocation_fn_p (tree fn)
>      SIZE is the size of the memory block to be deleted.
>      GLOBAL_P is true if the delete-expression should not consider
>      class-specific delete operators.
> +   TWO_ARGS_PRIORITY_P is true if a two argument usual deallocation should be
> +   chosen in preference to the single argument version in a class context.
>      PLACEMENT is the corresponding placement new call, or NULL_TREE.
>   
>      If this call to "operator delete" is being generated as part to
> @@ -7859,10 +7861,10 @@ usual_deallocation_fn_p (tree fn)
>      we call a deallocation function), then ALLOC_FN is the allocation
>      function.  */
>   
> -tree
> -build_op_delete_call (enum tree_code code, tree addr, tree size,
> -		      bool global_p, tree placement,
> -		      tree alloc_fn, tsubst_flags_t complain)
> +static tree
> +build_op_delete_call_1 (enum tree_code code, tree addr, tree size,
> +			bool global_p, bool two_args_priority_p, tree placement,
> +			tree alloc_fn, tsubst_flags_t complain)
>   {
>     tree fn = NULL_TREE;
>     tree fns, fnname, type, t;
> @@ -8041,7 +8043,7 @@ build_op_delete_call (enum tree_code code, tree addr, tree size,
>   	    /* -- If the deallocation functions have class scope, the one
>   	       without a parameter of type std::size_t is selected.  */
>   	    bool want_size;
> -	    if (DECL_CLASS_SCOPE_P (fn))
> +	    if (DECL_CLASS_SCOPE_P (fn) && !two_args_priority_p)
>   	      want_size = false;
>   
>   	    /* -- If the type is complete and if, for the second alternative
> @@ -8179,6 +8181,30 @@ build_op_delete_call (enum tree_code code, tree addr, tree size,
>     return error_mark_node;
>   }
>   
> +/* Arguments as per build_op_delete_call_1 ().  */
> +
> +tree
> +build_op_delete_call (enum tree_code code, tree addr, tree size,
> +		      bool global_p, bool two_args_priority_p, tree placement,
> +		      tree alloc_fn, tsubst_flags_t complain)
> +{
> +  return build_op_delete_call_1 (code, addr, size, global_p,
> +				two_args_priority_p, placement, alloc_fn,
> +				complain);
> +}

Rather than having a new overload with the same name and a bool 
parameter that will only be used to pass "true", let's give it a 
different name with no new parameter that passes "true" to _1.  Perhaps 
build_op_delete_call_coro, and call the new parameter to _1 coro_p 
instead of two_args_priority_p?

...
> +/* Build the ramp function.
> +   Here we take the original function definition which has now had its body
> +   removed, and use it as the declaration of the ramp which both replaces the
> +   user's written function at call sites, and is responsible for starting
> +   the coroutine it defined.
> +   returns NULL_TREE on error or an expression for the frame size.
> +
> +   We should arrive here with the state of the compiler as if we had just
> +   executed start_preparsed_function().  */
> +
> +bool
> +cp_coroutine_transform::build_ramp_function ()
> +{
> +  gcc_checking_assert (current_binding_level
> +		       && current_binding_level->kind == sk_function_parms);
> +
> +  /* This is completely synthetic code, if we find an issue then we have not
> +     much chance to point at the most useful place in the user's code.  In
> +     lieu of this use the function start - so at least the diagnostic relates
> +     to something that the user can inspect.  */
> +  iloc_sentinel saved_position (fn_start);
> +  location_t loc = fn_start;
> +
> +  tree promise_type = get_coroutine_promise_type (orig_fn_decl);
> +  tree fn_return_type = TREE_TYPE (TREE_TYPE (orig_fn_decl));
> +
> +  /* [dcl.fct.def.coroutine] / 10 (part1)
> +    The unqualified-id get_return_object_on_allocation_failure is looked up
> +    in the scope of the promise type by class member access lookup.  */
> +
> +  /* We don't require this,  but, if the lookup succeeds, then the function
> +     must be usable, punt if it is not.  */
> +  tree grooaf_meth
> +    = lookup_promise_method (orig_fn_decl,
> +			     coro_gro_on_allocation_fail_identifier, loc,
> +			     /*musthave*/ false);
> +  tree grooaf = NULL_TREE;
> +  tree dummy_promise
> +    = build_dummy_object (get_coroutine_promise_type (orig_fn_decl));
> +  if (grooaf_meth && grooaf_meth != error_mark_node)
> +    {
> +      grooaf
> +	= coro_build_promise_expression (orig_fn_decl, dummy_promise,
> +					 coro_gro_on_allocation_fail_identifier,
> +					 fn_start, NULL, /*musthave=*/false);
> +
> +      /* That should succeed.  */
> +      if (!grooaf || grooaf == error_mark_node)
> +	{
> +	  error_at (fn_start, "%qE is provided by %qT but is not usable with"
> +		    " the function %qD", coro_gro_on_allocation_fail_identifier,
> +		    promise_type, orig_fn_decl);
> +	  return false;
> +	}
> +    }
> +
> +  /* Check early for usable allocator/deallocator, without which we cannot
> +     build a useful ramp; early exit if they are not available or usable.  */
> +
> +  frame_size = TYPE_SIZE_UNIT (frame_type);
> +
> +  /* Make a var to represent the frame pointer early.  Initialize to zero so
> +     that we can pass it to the IFN_CO_FRAME (to give that access to the frame
> +     type).  */
> +  tree coro_fp = coro_build_artificial_var (loc, "_Coro_frameptr",
> +					    frame_ptr_type, orig_fn_decl,
> +					    NULL_TREE);
> +
> +  tree new_fn_call
> +    = build_coroutine_frame_alloc_expr (promise_type, orig_fn_decl, fn_start,
> +					grooaf, &param_uses, frame_size);
> +
> +  /* We must have a useable allocator to proceed.  */
> +  if (!new_fn_call || new_fn_call == error_mark_node)
> +    return false;
> +
> +  /* Likewise, we need the DTOR to delete the frame.  */
> +  tree delete_frame_call
> +    = build_coroutine_frame_delete_expr (coro_fp, orig_fn_decl, frame_size,
> +					 promise_type, fn_start);
> +  if (!delete_frame_call || delete_frame_call == error_mark_node)
> +    return false;
> +
> +  /* At least verify we can lookup the get return object method.  */
> +  tree get_ro_meth
> +    = lookup_promise_method (orig_fn_decl,
> +			     coro_get_return_object_identifier, loc,
> +			     /*musthave*/ true);
> +  if (!get_ro_meth || get_ro_meth == error_mark_node)
> +    return false;
> +
> +  /* So now construct the Ramp: */
> +
> +  /* In generated code, for the most part, we need to set the location to
> +     'unknown' to avoid the debugger jumping around.  */

I don't think that applies to an entirely artificial function like the 
ramp?  Where else would the debugger jump to?

> +  input_location = loc = UNKNOWN_LOCATION;
> +
> +  tree ramp_fnbody = begin_function_body ();
> +  /* Now build the ramp function pieces.  */
> +  tree ramp_bind = build3 (BIND_EXPR, void_type_node, NULL, NULL, NULL);
> +  add_stmt (ramp_bind);
> +  tree ramp_outer_bind = push_stmt_list ();
> +  tree varlist = coro_fp;
> +
> +  /* To signal that we need to cleanup copied function args.  */
> +  if (flag_exceptions && DECL_ARGUMENTS (orig_fn_decl))
> +    for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
> +	arg = DECL_CHAIN (arg))
> +      {
> +	param_info *parm_i = param_uses.get (arg);
> +	gcc_checking_assert (parm_i);
> +	if (parm_i->trivial_dtor)
> +	  continue;
> +	DECL_CHAIN (parm_i->guard_var) = varlist;
> +	varlist = parm_i->guard_var;
> +      }
> +
> +  /* Signal that we need to clean up the promise object on exception.  */
> +  tree coro_promise_live
> +    = coro_build_artificial_var (loc, "_Coro_promise_live", boolean_type_node,
> +				 orig_fn_decl, boolean_false_node);
> +  DECL_CHAIN (coro_promise_live) = varlist;
> +  varlist = coro_promise_live;
> +
> +  /* When the get-return-object is in the RETURN slot, we need to arrange for
> +     cleanup on exception.  */
> +  tree coro_gro_live
> +    = coro_build_artificial_var (loc, "_Coro_gro_live", boolean_type_node,
> +				 orig_fn_decl, boolean_false_node);
> +
> +  DECL_CHAIN (coro_gro_live) = varlist;
> +  varlist = coro_gro_live;
> +
> +  /* Collected the scope vars we need ... only one for now. */
> +  BIND_EXPR_VARS (ramp_bind) = nreverse (varlist);
> +
> +  /* We're now going to create a new top level scope block for the ramp
> +     function.  */
> +  tree top_block = make_node (BLOCK);
> +
> +  BIND_EXPR_BLOCK (ramp_bind) = top_block;
> +  BLOCK_VARS (top_block) = BIND_EXPR_VARS (ramp_bind);
> +  BLOCK_SUBBLOCKS (top_block) = NULL_TREE;
> +  current_binding_level->blocks = top_block;
> +
> +  add_decl_expr (coro_fp);
> +  if (flag_exceptions && DECL_ARGUMENTS (orig_fn_decl))
> +    for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
> +	arg = DECL_CHAIN (arg))
> +      {
> +	param_info *parm_i = param_uses.get (arg);
> +	if (parm_i->trivial_dtor)
> +	  continue;
> +	add_decl_expr (parm_i->guard_var);
> +      }
> +  add_decl_expr (coro_promise_live);
> +  add_decl_expr (coro_gro_live);
> +
> +  /* Build the frame.  */
> +
> +  /* The CO_FRAME internal function is a mechanism to allow the middle end
> +     to adjust the allocation in response to optimizations.  We provide the
> +     current conservative estimate of the frame size (as per the current)
> +     computed layout.  */
> +
> +  tree resizeable
> +    = build_call_expr_internal_loc (loc, IFN_CO_FRAME, size_type_node, 2,
> +				    frame_size,
> +				    build_zero_cst (frame_ptr_type));
> +  CALL_EXPR_ARG (new_fn_call, 0) = resizeable;
> +  tree allocated = build1 (CONVERT_EXPR, frame_ptr_type, new_fn_call);
>     tree r = cp_build_init_expr (coro_fp, allocated);
>     finish_expr_stmt (r);
>   
> @@ -4943,8 +4976,7 @@ cp_coroutine_transform::complete_ramp_function ()
>         BIND_EXPR_BODY (ramp_bind) = pop_stmt_list (ramp_outer_bind);
>         /* Suppress warnings about the missing return value.  */
>         suppress_warning (orig_fn_decl, OPT_Wreturn_type);
> -      valid_coroutine = false;
> -      return;
> +      return false;
>       }
>   
>     tree gro_context_body = push_stmt_list ();
> @@ -5029,9 +5061,6 @@ cp_coroutine_transform::complete_ramp_function ()
>     r = build_call_expr_loc (fn_start, resumer, 1, coro_fp);
>     finish_expr_stmt (r);
>   
> -  /* Switch to using 'input_location' as the loc, since we're now more
> -     logically doing things related to the end of the function.  */
> -
>     /* The ramp is done, we just need the return value.
>        [dcl.fct.def.coroutine] / 7
>        The expression promise.get_return_object() is used to initialize the
> @@ -5061,14 +5090,17 @@ cp_coroutine_transform::complete_ramp_function ()
>     else
>       {
>         /* We can't initialize a non-class return value from void.  */
> -      error_at (input_location, "cannot initialize a return object of type"
> +      error_at (fn_start, "cannot initialize a return object of type"
>   		" %qT with an rvalue of type %<void%>", fn_return_type);
> -      r = error_mark_node;
> -      valid_coroutine = false;
> -      return;
> +      return false;
>       }
>   
> +  /* Without a relevant location, bad conversions in finish_return_stmt result
> +     in unusable diagnostics, since there is not even a mention of the
> +     relevant function.  */

...and if you don't switch to UNKNOWN_LOCATION above, you don't need to 
mess with input_location here.

Jason
diff mbox series

Patch

diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc
index 0fe679aae9f..377882a1c61 100644
--- a/gcc/cp/call.cc
+++ b/gcc/cp/call.cc
@@ -7851,6 +7851,8 @@  usual_deallocation_fn_p (tree fn)
    SIZE is the size of the memory block to be deleted.
    GLOBAL_P is true if the delete-expression should not consider
    class-specific delete operators.
+   TWO_ARGS_PRIORITY_P is true if a two argument usual deallocation should be
+   chosen in preference to the single argument version in a class context.
    PLACEMENT is the corresponding placement new call, or NULL_TREE.
 
    If this call to "operator delete" is being generated as part to
@@ -7859,10 +7861,10 @@  usual_deallocation_fn_p (tree fn)
    we call a deallocation function), then ALLOC_FN is the allocation
    function.  */
 
-tree
-build_op_delete_call (enum tree_code code, tree addr, tree size,
-		      bool global_p, tree placement,
-		      tree alloc_fn, tsubst_flags_t complain)
+static tree
+build_op_delete_call_1 (enum tree_code code, tree addr, tree size,
+			bool global_p, bool two_args_priority_p, tree placement,
+			tree alloc_fn, tsubst_flags_t complain)
 {
   tree fn = NULL_TREE;
   tree fns, fnname, type, t;
@@ -8041,7 +8043,7 @@  build_op_delete_call (enum tree_code code, tree addr, tree size,
 	    /* -- If the deallocation functions have class scope, the one
 	       without a parameter of type std::size_t is selected.  */
 	    bool want_size;
-	    if (DECL_CLASS_SCOPE_P (fn))
+	    if (DECL_CLASS_SCOPE_P (fn) && !two_args_priority_p)
 	      want_size = false;
 
 	    /* -- If the type is complete and if, for the second alternative
@@ -8179,6 +8181,30 @@  build_op_delete_call (enum tree_code code, tree addr, tree size,
   return error_mark_node;
 }
 
+/* Arguments as per build_op_delete_call_1 ().  */
+
+tree
+build_op_delete_call (enum tree_code code, tree addr, tree size,
+		      bool global_p, bool two_args_priority_p, tree placement,
+		      tree alloc_fn, tsubst_flags_t complain)
+{
+  return build_op_delete_call_1 (code, addr, size, global_p,
+				two_args_priority_p, placement, alloc_fn,
+				complain);
+}
+
+/* Arguments as per build_op_delete_call_1 ().  */
+
+tree
+build_op_delete_call (enum tree_code code, tree addr, tree size,
+		      bool global_p, tree placement, tree alloc_fn,
+		      tsubst_flags_t complain)
+{
+  return build_op_delete_call_1 (code, addr, size, global_p,
+				/*two_args_priority_p*/false, placement,
+				alloc_fn, complain);
+}
+
 /* Issue diagnostics about a disallowed access of DECL, using DIAG_DECL
    in the diagnostics.
 
diff --git a/gcc/cp/coroutines.cc b/gcc/cp/coroutines.cc
index a7d4021c6c1..8cdc76a6054 100644
--- a/gcc/cp/coroutines.cc
+++ b/gcc/cp/coroutines.cc
@@ -2202,55 +2202,7 @@  transform_local_var_uses (tree *stmt, int *do_subtree, void *d)
    argument.  */
 
 static tree
-coro_get_frame_dtor (tree coro_fp, tree orig, tree frame_size,
-		     tree promise_type, location_t loc)
-{
-  tree del_coro_fr = NULL_TREE;
-  tree frame_arg = build1 (CONVERT_EXPR, ptr_type_node, coro_fp);
-  tree delname = ovl_op_identifier (false, DELETE_EXPR);
-  tree fns = lookup_promise_method (orig, delname, loc,
-					/*musthave=*/false);
-  if (fns && BASELINK_P (fns))
-    {
-      /* Look for sized version first, since this takes precedence.  */
-      vec<tree, va_gc> *args = make_tree_vector ();
-      vec_safe_push (args, frame_arg);
-      vec_safe_push (args, frame_size);
-      tree dummy_promise = build_dummy_object (promise_type);
-
-      /* It's OK to fail for this one... */
-      del_coro_fr = build_new_method_call (dummy_promise, fns, &args,
-					   NULL_TREE, LOOKUP_NORMAL, NULL,
-					   tf_none);
-
-      if (!del_coro_fr || del_coro_fr == error_mark_node)
-	{
-	  release_tree_vector (args);
-	  args = make_tree_vector_single (frame_arg);
-	  del_coro_fr = build_new_method_call (dummy_promise, fns, &args,
-					       NULL_TREE, LOOKUP_NORMAL, NULL,
-					       tf_none);
-	}
-
-      /* But one of them must succeed, or the program is ill-formed.  */
-      if (!del_coro_fr || del_coro_fr == error_mark_node)
-	{
-	  error_at (loc, "%qE is provided by %qT but is not usable with"
-		  " the function signature %qD", delname, promise_type, orig);
-	  del_coro_fr = error_mark_node;
-	}
-    }
-  else
-    {
-      del_coro_fr = build_op_delete_call (DELETE_EXPR, frame_arg, frame_size,
-					  /*global_p=*/true, /*placement=*/NULL,
-					  /*alloc_fn=*/NULL,
-					  tf_warning_or_error);
-      if (!del_coro_fr || del_coro_fr == error_mark_node)
-	del_coro_fr = error_mark_node;
-    }
-  return del_coro_fr;
-}
+build_coroutine_frame_delete_expr (tree, tree, tree, tree, location_t);
 
 /* The actor transform.  */
 
@@ -2484,8 +2436,9 @@  build_actor_fn (location_t loc, tree coro_frame_type, tree actor, tree fnbody,
     }
 
   /* Build the frame DTOR.  */
-  tree del_coro_fr = coro_get_frame_dtor (actor_fp, orig, frame_size,
-					  promise_type, loc);
+  tree del_coro_fr
+    = build_coroutine_frame_delete_expr (actor_fp, orig, frame_size,
+					 promise_type, loc);
   finish_expr_stmt (del_coro_fr);
   finish_then_clause (need_free_if);
   tree scope = IF_SCOPE (need_free_if);
@@ -4466,134 +4419,24 @@  split_coroutine_body_from_ramp (tree fndecl)
   return body;
 }
 
-/* Build the ramp function.
-   Here we take the original function definition which has now had its body
-   removed, and use it as the declaration of the ramp which both replaces the
-   user's written function at call sites, and is responsible for starting
-   the coroutine it defined.
-   returns NULL_TREE on error or an expression for the frame size.
-
-   We should arrive here with the state of the compiler as if we had just
-   executed start_preparsed_function().  */
+/* Build the expression to allocate the coroutine frame according to the
+   rules of [dcl.fct.def.coroutine] / 9.  */
 
-void
-cp_coroutine_transform::complete_ramp_function ()
+static tree
+build_coroutine_frame_alloc_expr (tree promise_type, tree orig_fn_decl,
+				  location_t fn_start, tree grooaf,
+				  hash_map<tree, param_info> *param_uses,
+				  tree frame_size)
 {
-  gcc_checking_assert (current_binding_level
-		       && current_binding_level->kind == sk_function_parms);
-
-  /* Avoid the code here attaching a location that makes the debugger jump.  */
-  location_t loc = fn_start;
-
-  tree promise_type = get_coroutine_promise_type (orig_fn_decl);
-  tree fn_return_type = TREE_TYPE (TREE_TYPE (orig_fn_decl));
-
-  /* Ramp: */
-  tree ramp_fnbody = begin_function_body ();
-  /* Now build the ramp function pieces.  */
-  tree ramp_bind = build3 (BIND_EXPR, void_type_node, NULL, NULL, NULL);
-  add_stmt (ramp_bind);
-  tree ramp_outer_bind = push_stmt_list ();
-
-  tree zeroinit = build1_loc (loc, CONVERT_EXPR,
-			      frame_ptr_type, nullptr_node);
-  tree coro_fp = coro_build_artificial_var (loc, "_Coro_frameptr",
-					    frame_ptr_type, orig_fn_decl,
-					    zeroinit);
-  tree varlist = coro_fp;
-
-  /* To signal that we need to cleanup copied function args.  */
-  if (flag_exceptions && DECL_ARGUMENTS (orig_fn_decl))
-    for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
-	arg = DECL_CHAIN (arg))
-      {
-	param_info *parm_i = param_uses.get (arg);
-	gcc_checking_assert (parm_i);
-	if (parm_i->trivial_dtor)
-	  continue;
-	DECL_CHAIN (parm_i->guard_var) = varlist;
-	varlist = parm_i->guard_var;
-      }
-
-  /* Signal that we need to clean up the promise object on exception.  */
-  tree coro_promise_live
-    = coro_build_artificial_var (loc, "_Coro_promise_live",
-				 boolean_type_node, orig_fn_decl, boolean_false_node);
-  DECL_CHAIN (coro_promise_live) = varlist;
-  varlist = coro_promise_live;
-
-  /* When the get-return-object is in the RETURN slot, we need to arrange for
-     cleanup on exception.  */
-  tree coro_gro_live
-    = coro_build_artificial_var (loc, "_Coro_gro_live",
-				 boolean_type_node, orig_fn_decl, boolean_false_node);
-
-  DECL_CHAIN (coro_gro_live) = varlist;
-  varlist = coro_gro_live;
-
-  /* Collected the scope vars we need ... only one for now. */
-  BIND_EXPR_VARS (ramp_bind) = nreverse (varlist);
-
-  /* We're now going to create a new top level scope block for the ramp
-     function.  */
-  tree top_block = make_node (BLOCK);
-
-  BIND_EXPR_BLOCK (ramp_bind) = top_block;
-  BLOCK_VARS (top_block) = BIND_EXPR_VARS (ramp_bind);
-  BLOCK_SUBBLOCKS (top_block) = NULL_TREE;
-  current_binding_level->blocks = top_block;
-
-  /* The decl_expr for the coro frame pointer, initialize to zero so that we
-     can pass it to the IFN_CO_FRAME (since there's no way to pass a type,
-     directly apparently).  This avoids a "used uninitialized" warning.  */
-
-  add_decl_expr (coro_fp);
-  if (flag_exceptions && DECL_ARGUMENTS (orig_fn_decl))
-    for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
-	arg = DECL_CHAIN (arg))
-      {
-	param_info *parm_i = param_uses.get (arg);
-	if (parm_i->trivial_dtor)
-	  continue;
-	add_decl_expr (parm_i->guard_var);
-      }
-  add_decl_expr (coro_promise_live);
-  add_decl_expr (coro_gro_live);
-
-  /* The CO_FRAME internal function is a mechanism to allow the middle end
-     to adjust the allocation in response to optimizations.  We provide the
-     current conservative estimate of the frame size (as per the current)
-     computed layout.  */
-  frame_size = TYPE_SIZE_UNIT (frame_type);
-  tree resizeable
-    = build_call_expr_internal_loc (loc, IFN_CO_FRAME, size_type_node, 2,
-				    frame_size, coro_fp);
-
-  /* [dcl.fct.def.coroutine] / 10 (part1)
-    The unqualified-id get_return_object_on_allocation_failure is looked up
-    in the scope of the promise type by class member access lookup.  */
-
-  /* We don't require this, so coro_build_promise_expression can return NULL,
-     but, if the lookup succeeds, then the function must be usable.  */
-  tree dummy_promise = build_dummy_object (get_coroutine_promise_type (orig_fn_decl));
-  tree grooaf
-    = coro_build_promise_expression (orig_fn_decl, dummy_promise,
-				     coro_gro_on_allocation_fail_identifier,
-				     loc, NULL, /*musthave=*/false);
-
-  /* however, should that fail, returning an error, the later stages can't
-     handle the erroneous expression, so we reset the call as if it was
-     absent.  */
-  if (grooaf == error_mark_node)
-    grooaf = NULL_TREE;
-
   /* Allocate the frame, this has several possibilities:
      [dcl.fct.def.coroutine] / 9 (part 1)
      The allocation function’s name is looked up in the scope of the promise
-     type.  It's not a failure for it to be absent see part 4, below.  */
+     type.  It is not a failure for it to be absent see part 4, below.  */
 
   tree nwname = ovl_op_identifier (false, NEW_EXPR);
-  tree new_fn = NULL_TREE;
+  tree new_fn_call = NULL_TREE;
+  tree dummy_promise
+    = build_dummy_object (get_coroutine_promise_type (orig_fn_decl));
 
   if (TYPE_HAS_NEW_OPERATOR (promise_type))
     {
@@ -4606,12 +4449,12 @@  cp_coroutine_transform::complete_ramp_function ()
 	requested, and has type std::size_t.  The lvalues p1...pn are the
 	succeeding arguments..  */
       vec<tree, va_gc> *args = make_tree_vector ();
-      vec_safe_push (args, resizeable); /* Space needed.  */
+      vec_safe_push (args, frame_size); /* Space needed.  */
 
       for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
 	   arg = DECL_CHAIN (arg))
 	{
-	  param_info *parm_i = param_uses.get (arg);
+	  param_info *parm_i = param_uses->get (arg);
 	  gcc_checking_assert (parm_i);
 	  if (parm_i->this_ptr || parm_i->lambda_cobj)
 	    {
@@ -4628,18 +4471,18 @@  cp_coroutine_transform::complete_ramp_function ()
       /* Note the function selected; we test to see if it's NOTHROW.  */
       tree func;
       /* Failure is not an error for this attempt.  */
-      new_fn = build_new_method_call (dummy_promise, fns, &args, NULL,
+      new_fn_call = build_new_method_call (dummy_promise, fns, &args, NULL,
 				      LOOKUP_NORMAL, &func, tf_none);
       release_tree_vector (args);
 
-      if (new_fn == error_mark_node)
+      if (new_fn_call == error_mark_node)
 	{
 	  /* [dcl.fct.def.coroutine] / 9 (part 3)
 	    If no viable function is found, overload resolution is performed
 	    again on a function call created by passing just the amount of
 	    space required as an argument of type std::size_t.  */
-	  args = make_tree_vector_single (resizeable); /* Space needed.  */
-	  new_fn = build_new_method_call (dummy_promise, fns, &args,
+	  args = make_tree_vector_single (frame_size); /* Space needed.  */
+	  new_fn_call = build_new_method_call (dummy_promise, fns, &args,
 					  NULL_TREE, LOOKUP_NORMAL, &func,
 					  tf_none);
 	  release_tree_vector (args);
@@ -4647,21 +4490,18 @@  cp_coroutine_transform::complete_ramp_function ()
 
      /* However, if the promise provides an operator new, then one of these
 	two options must be available.  */
-    if (new_fn == error_mark_node)
+    if (new_fn_call == error_mark_node)
       {
 	error_at (fn_start, "%qE is provided by %qT but is not usable with"
 		  " the function signature %qD", nwname, promise_type,
 		  orig_fn_decl);
-	new_fn = error_mark_node;
-	valid_coroutine = false;
-	return;
+	return error_mark_node;
       }
     else if (grooaf && !TYPE_NOTHROW_P (TREE_TYPE (func)))
       {
 	error_at (fn_start, "%qE is provided by %qT but %qE is not marked"
 		" %<throw()%> or %<noexcept%>", grooaf, promise_type, nwname);
-	valid_coroutine = false;
-	return;
+	return error_mark_node;
       }
     else if (!grooaf && TYPE_NOTHROW_P (TREE_TYPE (func)))
       warning_at (fn_start, 0, "%qE is marked %<throw()%> or %<noexcept%> but"
@@ -4693,31 +4533,224 @@  cp_coroutine_transform::complete_ramp_function ()
 					       LOOK_want::NORMAL,
 					       /*complain=*/true);
 	  if (!std_nt || std_nt == error_mark_node)
-	    error_at (fn_start, "%qE is provided by %qT but %<std::nothrow%> "
-		      "cannot be found", grooaf, promise_type);
+	    {
+	      /* Something is seriously wrong, punt.  */
+	      error_at (fn_start, "%qE is provided by %qT but %<std::nothrow%>"
+			" cannot be found", grooaf, promise_type);
+	      return error_mark_node;
+	    }
 	  vec_safe_push (args, std_nt);
 	}
 
       /* If we get to this point, we must succeed in looking up the global
-	 operator new for the params provided.  Extract a simplified version
-	 of the machinery from build_operator_new_call.  This can update the
-	 frame size.  */
+	 operator new for the params provided.  Since we are not setting
+	 size_check or cookie, we expect frame_size to be unaltered.  */
       tree cookie = NULL;
-      new_fn = build_operator_new_call (nwname, &args, &frame_size, &cookie,
-					/*align_arg=*/NULL,
-					/*size_check=*/NULL, /*fn=*/NULL,
-					tf_warning_or_error);
-      resizeable = build_call_expr_internal_loc
-	(loc, IFN_CO_FRAME, size_type_node, 2, frame_size, coro_fp);
-      /* If the operator call fails for some reason, then don't try to
-	 amend it.  */
-      if (new_fn != error_mark_node)
-	CALL_EXPR_ARG (new_fn, 0) = resizeable;
-
+      new_fn_call = build_operator_new_call (nwname, &args, &frame_size,
+					     &cookie, /*align_arg=*/NULL,
+					     /*size_check=*/NULL, /*fn=*/NULL,
+					     tf_warning_or_error);
       release_tree_vector (args);
     }
+  return new_fn_call;
+}
 
-  tree allocated = build1 (CONVERT_EXPR, frame_ptr_type, new_fn);
+/* Build an expression to delete the coroutine state frame.  */
+
+static tree
+build_coroutine_frame_delete_expr (tree coro_fp, tree orig, tree frame_size,
+				   tree promise_type, location_t loc)
+{
+  /* Cast the frame pointer to a pointer to promise so that the build op
+     delete call will search the promise.  */
+  tree pptr_type = build_pointer_type (promise_type);
+  tree frame_arg = build1_loc (loc, CONVERT_EXPR, pptr_type, coro_fp);
+  /* [dcl.fct.def.coroutine] / 12 sentence 3:
+     If both a usual deallocation function with only a pointer parameter and
+     a usual deallocation function with both a pointer parameter and a size
+     parameter are found, then the selected deallocation function shall be the
+     one with two parameters.  */
+  tree del_coro_fr
+    = build_op_delete_call (DELETE_EXPR, frame_arg, frame_size,
+			    /*global_p=*/false, /*two_args_priority_p*/true,
+			    /*placement=*/NULL, /*alloc_fn=*/NULL,
+			    tf_warning_or_error);
+  if (!del_coro_fr || del_coro_fr == error_mark_node)
+    return error_mark_node;
+  return del_coro_fr;
+}
+
+/* Build the ramp function.
+   Here we take the original function definition which has now had its body
+   removed, and use it as the declaration of the ramp which both replaces the
+   user's written function at call sites, and is responsible for starting
+   the coroutine it defined.
+   returns NULL_TREE on error or an expression for the frame size.
+
+   We should arrive here with the state of the compiler as if we had just
+   executed start_preparsed_function().  */
+
+bool
+cp_coroutine_transform::build_ramp_function ()
+{
+  gcc_checking_assert (current_binding_level
+		       && current_binding_level->kind == sk_function_parms);
+
+  /* This is completely synthetic code, if we find an issue then we have not
+     much chance to point at the most useful place in the user's code.  In
+     lieu of this use the function start - so at least the diagnostic relates
+     to something that the user can inspect.  */
+  iloc_sentinel saved_position (fn_start);
+  location_t loc = fn_start;
+
+  tree promise_type = get_coroutine_promise_type (orig_fn_decl);
+  tree fn_return_type = TREE_TYPE (TREE_TYPE (orig_fn_decl));
+
+  /* [dcl.fct.def.coroutine] / 10 (part1)
+    The unqualified-id get_return_object_on_allocation_failure is looked up
+    in the scope of the promise type by class member access lookup.  */
+
+  /* We don't require this,  but, if the lookup succeeds, then the function
+     must be usable, punt if it is not.  */
+  tree grooaf_meth
+    = lookup_promise_method (orig_fn_decl,
+			     coro_gro_on_allocation_fail_identifier, loc,
+			     /*musthave*/ false);
+  tree grooaf = NULL_TREE;
+  tree dummy_promise
+    = build_dummy_object (get_coroutine_promise_type (orig_fn_decl));
+  if (grooaf_meth && grooaf_meth != error_mark_node)
+    {
+      grooaf
+	= coro_build_promise_expression (orig_fn_decl, dummy_promise,
+					 coro_gro_on_allocation_fail_identifier,
+					 fn_start, NULL, /*musthave=*/false);
+
+      /* That should succeed.  */
+      if (!grooaf || grooaf == error_mark_node)
+	{
+	  error_at (fn_start, "%qE is provided by %qT but is not usable with"
+		    " the function %qD", coro_gro_on_allocation_fail_identifier,
+		    promise_type, orig_fn_decl);
+	  return false;
+	}
+    }
+
+  /* Check early for usable allocator/deallocator, without which we cannot
+     build a useful ramp; early exit if they are not available or usable.  */
+
+  frame_size = TYPE_SIZE_UNIT (frame_type);
+
+  /* Make a var to represent the frame pointer early.  Initialize to zero so
+     that we can pass it to the IFN_CO_FRAME (to give that access to the frame
+     type).  */
+  tree coro_fp = coro_build_artificial_var (loc, "_Coro_frameptr",
+					    frame_ptr_type, orig_fn_decl,
+					    NULL_TREE);
+
+  tree new_fn_call
+    = build_coroutine_frame_alloc_expr (promise_type, orig_fn_decl, fn_start,
+					grooaf, &param_uses, frame_size);
+
+  /* We must have a useable allocator to proceed.  */
+  if (!new_fn_call || new_fn_call == error_mark_node)
+    return false;
+
+  /* Likewise, we need the DTOR to delete the frame.  */
+  tree delete_frame_call
+    = build_coroutine_frame_delete_expr (coro_fp, orig_fn_decl, frame_size,
+					 promise_type, fn_start);
+  if (!delete_frame_call || delete_frame_call == error_mark_node)
+    return false;
+
+  /* At least verify we can lookup the get return object method.  */
+  tree get_ro_meth
+    = lookup_promise_method (orig_fn_decl,
+			     coro_get_return_object_identifier, loc,
+			     /*musthave*/ true);
+  if (!get_ro_meth || get_ro_meth == error_mark_node)
+    return false;
+
+  /* So now construct the Ramp: */
+
+  /* In generated code, for the most part, we need to set the location to
+     'unknown' to avoid the debugger jumping around.  */
+  input_location = loc = UNKNOWN_LOCATION;
+
+  tree ramp_fnbody = begin_function_body ();
+  /* Now build the ramp function pieces.  */
+  tree ramp_bind = build3 (BIND_EXPR, void_type_node, NULL, NULL, NULL);
+  add_stmt (ramp_bind);
+  tree ramp_outer_bind = push_stmt_list ();
+  tree varlist = coro_fp;
+
+  /* To signal that we need to cleanup copied function args.  */
+  if (flag_exceptions && DECL_ARGUMENTS (orig_fn_decl))
+    for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
+	arg = DECL_CHAIN (arg))
+      {
+	param_info *parm_i = param_uses.get (arg);
+	gcc_checking_assert (parm_i);
+	if (parm_i->trivial_dtor)
+	  continue;
+	DECL_CHAIN (parm_i->guard_var) = varlist;
+	varlist = parm_i->guard_var;
+      }
+
+  /* Signal that we need to clean up the promise object on exception.  */
+  tree coro_promise_live
+    = coro_build_artificial_var (loc, "_Coro_promise_live", boolean_type_node,
+				 orig_fn_decl, boolean_false_node);
+  DECL_CHAIN (coro_promise_live) = varlist;
+  varlist = coro_promise_live;
+
+  /* When the get-return-object is in the RETURN slot, we need to arrange for
+     cleanup on exception.  */
+  tree coro_gro_live
+    = coro_build_artificial_var (loc, "_Coro_gro_live", boolean_type_node,
+				 orig_fn_decl, boolean_false_node);
+
+  DECL_CHAIN (coro_gro_live) = varlist;
+  varlist = coro_gro_live;
+
+  /* Collected the scope vars we need ... only one for now. */
+  BIND_EXPR_VARS (ramp_bind) = nreverse (varlist);
+
+  /* We're now going to create a new top level scope block for the ramp
+     function.  */
+  tree top_block = make_node (BLOCK);
+
+  BIND_EXPR_BLOCK (ramp_bind) = top_block;
+  BLOCK_VARS (top_block) = BIND_EXPR_VARS (ramp_bind);
+  BLOCK_SUBBLOCKS (top_block) = NULL_TREE;
+  current_binding_level->blocks = top_block;
+
+  add_decl_expr (coro_fp);
+  if (flag_exceptions && DECL_ARGUMENTS (orig_fn_decl))
+    for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
+	arg = DECL_CHAIN (arg))
+      {
+	param_info *parm_i = param_uses.get (arg);
+	if (parm_i->trivial_dtor)
+	  continue;
+	add_decl_expr (parm_i->guard_var);
+      }
+  add_decl_expr (coro_promise_live);
+  add_decl_expr (coro_gro_live);
+
+  /* Build the frame.  */
+
+  /* The CO_FRAME internal function is a mechanism to allow the middle end
+     to adjust the allocation in response to optimizations.  We provide the
+     current conservative estimate of the frame size (as per the current)
+     computed layout.  */
+
+  tree resizeable
+    = build_call_expr_internal_loc (loc, IFN_CO_FRAME, size_type_node, 2,
+				    frame_size,
+				    build_zero_cst (frame_ptr_type));
+  CALL_EXPR_ARG (new_fn_call, 0) = resizeable;
+  tree allocated = build1 (CONVERT_EXPR, frame_ptr_type, new_fn_call);
   tree r = cp_build_init_expr (coro_fp, allocated);
   finish_expr_stmt (r);
 
@@ -4943,8 +4976,7 @@  cp_coroutine_transform::complete_ramp_function ()
       BIND_EXPR_BODY (ramp_bind) = pop_stmt_list (ramp_outer_bind);
       /* Suppress warnings about the missing return value.  */
       suppress_warning (orig_fn_decl, OPT_Wreturn_type);
-      valid_coroutine = false;
-      return;
+      return false;
     }
 
   tree gro_context_body = push_stmt_list ();
@@ -5029,9 +5061,6 @@  cp_coroutine_transform::complete_ramp_function ()
   r = build_call_expr_loc (fn_start, resumer, 1, coro_fp);
   finish_expr_stmt (r);
 
-  /* Switch to using 'input_location' as the loc, since we're now more
-     logically doing things related to the end of the function.  */
-
   /* The ramp is done, we just need the return value.
      [dcl.fct.def.coroutine] / 7
      The expression promise.get_return_object() is used to initialize the
@@ -5061,14 +5090,17 @@  cp_coroutine_transform::complete_ramp_function ()
   else
     {
       /* We can't initialize a non-class return value from void.  */
-      error_at (input_location, "cannot initialize a return object of type"
+      error_at (fn_start, "cannot initialize a return object of type"
 		" %qT with an rvalue of type %<void%>", fn_return_type);
-      r = error_mark_node;
-      valid_coroutine = false;
-      return;
+      return false;
     }
 
+  /* Without a relevant location, bad conversions in finish_return_stmt result
+     in unusable diagnostics, since there is not even a mention of the
+     relevant function.  */
+  input_location = fn_start;
   finish_return_stmt (r);
+  input_location = UNKNOWN_LOCATION;
 
   if (gro_cleanup_stmt)
     {
@@ -5145,12 +5177,7 @@  cp_coroutine_transform::complete_ramp_function ()
 	}
 
       /* We always expect to delete the frame.  */
-      tree del_coro_fr = coro_get_frame_dtor (coro_fp, orig_fn_decl, frame_size,
-					      promise_type, loc);
-      if (!del_coro_fr || del_coro_fr == error_mark_node)
-	valid_coroutine = false; /* Do not add this.  */
-      else
-	finish_expr_stmt (del_coro_fr);
+      finish_expr_stmt (delete_frame_call);
       tree rethrow = build_throw (loc, NULL_TREE, tf_warning_or_error);
       suppress_warning (rethrow);
       finish_expr_stmt (rethrow);
@@ -5160,6 +5187,7 @@  cp_coroutine_transform::complete_ramp_function ()
 
   BIND_EXPR_BODY (ramp_bind) = pop_stmt_list (ramp_outer_bind);
   finish_function_body (ramp_fnbody);
+  return true;
 }
 
 /* ------- Encapsulate analysis of the couroutine -------- */
@@ -5297,7 +5325,7 @@  cp_coroutine_transform::apply_transforms ()
   BINFO_TYPE (TYPE_BINFO (frame_type)) = frame_type;
   frame_type = finish_struct (frame_type, NULL_TREE);
 
-  complete_ramp_function ();
+  valid_coroutine = build_ramp_function ();
 }
 
 /* Having analysed and collected the necessary data we are now in a position
diff --git a/gcc/cp/coroutines.h b/gcc/cp/coroutines.h
index c5b905cc9cc..d13bea0f302 100644
--- a/gcc/cp/coroutines.h
+++ b/gcc/cp/coroutines.h
@@ -128,5 +128,5 @@  private:
   bool valid_coroutine = false;
 
   void wrap_original_function_body ();
-  void complete_ramp_function ();
+  bool build_ramp_function ();
 };
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index cf4d6df90d8..f844ede7e79 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -6754,6 +6754,9 @@  extern bool usual_deallocation_fn_p		(tree);
 extern tree build_op_delete_call		(enum tree_code, tree, tree,
 						 bool, tree, tree,
 						 tsubst_flags_t);
+extern tree build_op_delete_call		(enum tree_code, tree, tree,
+						 bool, bool, tree, tree,
+						 tsubst_flags_t);
 extern bool can_convert				(tree, tree, tsubst_flags_t);
 extern bool can_convert_standard		(tree, tree, tsubst_flags_t);
 extern bool can_convert_arg			(tree, tree, tree, int,
diff --git a/gcc/testsuite/g++.dg/coroutines/coro-bad-alloc-01-bad-op-del.C b/gcc/testsuite/g++.dg/coroutines/coro-bad-alloc-01-bad-op-del.C
index 252cb5e442c..88321a28dde 100644
--- a/gcc/testsuite/g++.dg/coroutines/coro-bad-alloc-01-bad-op-del.C
+++ b/gcc/testsuite/g++.dg/coroutines/coro-bad-alloc-01-bad-op-del.C
@@ -6,7 +6,7 @@ 
 #include "coro1-allocators.h"
 
 struct coro1
-f ()  /* { dg-error {'operator delete' is provided by 'std::__n4861::__coroutine_traits_impl<coro1, void>::promise_type' \{aka 'coro1::promise_type'\} but is not usable with the function signature 'coro1 f\(\)'} } */
+f ()  /* { dg-error {no suitable 'operator delete' for.*promise_type.*} } */
 {
   co_return;
 }
diff --git a/gcc/testsuite/g++.dg/coroutines/coro-bad-gro-00-class-gro-scalar-return.C b/gcc/testsuite/g++.dg/coroutines/coro-bad-gro-00-class-gro-scalar-return.C
index 0512f03f4d0..605a2135878 100644
--- a/gcc/testsuite/g++.dg/coroutines/coro-bad-gro-00-class-gro-scalar-return.C
+++ b/gcc/testsuite/g++.dg/coroutines/coro-bad-gro-00-class-gro-scalar-return.C
@@ -33,11 +33,11 @@  struct std::coroutine_traits<R, HandleRef, T...> {
 };
 
 int
-my_coro (std::coroutine_handle<>& h)
+my_coro (std::coroutine_handle<>& h) // { dg-error {cannot convert 'Thing' to 'int' in return} }
 {
   PRINT ("coro1: about to return");
   co_return;
-} // { dg-error {cannot convert 'Thing' to 'int' in return} }
+}
 
 int main ()
 {
diff --git a/gcc/testsuite/g++.dg/coroutines/coro-bad-gro-01-void-gro-non-class-coro.C b/gcc/testsuite/g++.dg/coroutines/coro-bad-gro-01-void-gro-non-class-coro.C
index 2671ce7ca28..85aadad93b2 100644
--- a/gcc/testsuite/g++.dg/coroutines/coro-bad-gro-01-void-gro-non-class-coro.C
+++ b/gcc/testsuite/g++.dg/coroutines/coro-bad-gro-01-void-gro-non-class-coro.C
@@ -27,11 +27,11 @@  struct std::coroutine_traits<R, HandleRef, T...> {
 };
 
 int
-my_coro (std::coroutine_handle<>& h)
+my_coro (std::coroutine_handle<>& h) // { dg-error {cannot initialize a return object of type 'int' with an rvalue of type 'void'} }
 {
   PRINT ("coro1: about to return");
   co_return;
-} // { dg-error {cannot initialize a return object of type 'int' with an rvalue of type 'void'} }
+}
 
 int main ()
 {
diff --git a/gcc/testsuite/g++.dg/coroutines/coro-bad-grooaf-00-static.C b/gcc/testsuite/g++.dg/coroutines/coro-bad-grooaf-00-static.C
index e7d04346d57..6a41b4e85a2 100644
--- a/gcc/testsuite/g++.dg/coroutines/coro-bad-grooaf-00-static.C
+++ b/gcc/testsuite/g++.dg/coroutines/coro-bad-grooaf-00-static.C
@@ -7,9 +7,9 @@ 
 int used_grooaf = 0;
 
 struct coro1
-f () noexcept
+f () noexcept // { dg-error {cannot call member function 'coro1 coro1::promise_type::get_return_object_on_allocation_failure\(\)' without object} }
+// { dg-error {'get_return_object_on_allocation_failure' is provided by.*} "" { target *-*-* } .-1 }
 {
   PRINT ("coro1: about to return");
   co_return;
-} // { dg-error {cannot call member function 'coro1 coro1::promise_type::get_return_object_on_allocation_failure\(\)' without object} }
-
+}
diff --git a/gcc/testsuite/g++.dg/coroutines/ramp-return-b.C b/gcc/testsuite/g++.dg/coroutines/ramp-return-b.C
index d0e5d1f3c7f..dc21e974900 100644
--- a/gcc/testsuite/g++.dg/coroutines/ramp-return-b.C
+++ b/gcc/testsuite/g++.dg/coroutines/ramp-return-b.C
@@ -10,13 +10,13 @@  foo ()
 }
 
 task<int>
-bar ()
+bar ()  // { dg-error {use of deleted function 'task<T>::task\(const task<T>&\) \[with T = int\]'} }
 {
   co_return 0;
-} // { dg-error {use of deleted function 'task<T>::task\(const task<T>&\) \[with T = int\]'} }
+}
 
 task<std::vector<int>>
-baz ()
+baz ()  // { dg-error {use of deleted function 'task<T>::task\(const task<T>&\) \[with T = std::vector<int>\]'} }
 {
   co_return std::vector<int>();
-} // { dg-error {use of deleted function 'task<T>::task\(const task<T>&\) \[with T = std::vector<int>\]'} }
+}