This change makes it so that gigi uses a generic pointer type (ptr_type_node) 
for pointers to Taft Amendment types, which are kind of opaque pointer types.

Tested on x86_64-suse-linux, applied on the mainline.

However, this isn't sufficient for LTO's type canonical merging code, because 
the generic pointer type is the element type of an array instead of being used 
at top level, so the code issues the usual warning:

/home/eric/svn/gcc/gcc/testsuite/gnat.dg/lto19_pkg.ads:7:13: warning: type of 
'lto19_pkg__proc' does not match original declaration [-Wlto-type-mismatch]
/home/eric/svn/gcc/gcc/testsuite/gnat.dg/lto19_pkg.adb:7:3: note: 
'lto19_pkg__proc' was previously declared here
/home/eric/svn/gcc/gcc/testsuite/gnat.dg/lto19_pkg.adb:7:3: note: code may be 
misoptimized unless -fno-strict-aliasing is used

Jan, any idea on how to address this?


2016-07-14  Eric Botcazou  <ebotcazou@adacore.com>

	* gcc-interface/decl.c (gnat_to_gnu_entity) <E_Access_Type>: Also use
	the void pointer type if the designated type is incomplete and has no
	full view in LTO mode.
	<E_Access_Protected_Subprogram_Type>: Adjust comment.
	<E_Incomplete_Type>: Likewise.
	* gcc-interface/trans.c (Call_to_gnu): Do not convert to the type of
	the actual if it is a dummy type.


2016-07-14  Eric Botcazou  <ebotcazou@adacore.com>

        * gnat.dg/lto19.adb: New test.
        * gnat.dg/lto19_pkg.ad[sb]: New helper.

-- 
Eric Botcazou