[COMMITTED] ada: Spurious error on function returning CPP type

["Marc Poulhiès" <poulhies@adacore.com>]

From: Javier Miranda <miranda@adacore.com>

gcc/ada/

	* exp_ch6.adb
	(Needs_BIP_Alloc_Form): Return False for functions with foreign
	convention since we never use build-in-place for such functions.

Tested on x86_64-pc-linux-gnu, committed on master.

---
 gcc/ada/exp_ch6.adb | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/gcc/ada/exp_ch6.adb b/gcc/ada/exp_ch6.adb
index af7f75342fa..b8e5a720a7c 100644
--- a/gcc/ada/exp_ch6.adb
+++ b/gcc/ada/exp_ch6.adb
@@ -9435,9 +9435,14 @@ package body Exp_Ch6 is
       --  types, and those can be used to call primitives, so the formal needs
       --  to be passed to all such build-in-place functions, primitive or not.
 
+      --  We never use build-in-place if the function has foreign convention,
+      --  but note that it is OK for a build-in-place function to return a
+      --  type with a foreign convention because the machinery ensures there
+      --  is no copying.
+
       return not Restriction_Active (No_Secondary_Stack)
         and then (Needs_Secondary_Stack (Typ) or else Is_Tagged_Type (Typ))
-        and then not Has_Foreign_Convention (Typ);
+        and then not Has_Foreign_Convention (Func_Id);
    end Needs_BIP_Alloc_Form;
 
    -------------------------------------
-- 
2.40.0