On Mon, Sep 11, 2023 at 11:11:30PM +0200, Jakub Jelinek via Gcc-patches wrote:
> I think the divergence is whether called_by_test_5b returns the struct
> in registers or in memory.  If in memory (like in the x86_64 -m32 case), we have
>   [compound-assignment-1.c:71:21] D.3191 = called_by_test_5b (); [return slot optimization]
>   [compound-assignment-1.c:71:21 discrim 1] D.3191 ={v} {CLOBBER(eol)};
>   [compound-assignment-1.c:72:1] return;
> in the IL, while if in registers (like x86_64 -m64 case), just
>   [compound-assignment-1.c:71:21] D.3591 = called_by_test_5b ();
>   [compound-assignment-1.c:72:1] return;
>
> If you just want to avoid the differences, putting } on the same line as the
> call might be a usable workaround for that.

Here is the workaround in patch form.

2023-09-19  Jakub Jelinek  <jakub@redhat.com>

	PR testsuite/111377
	* c-c++-common/analyzer/compound-assignment-1.c (test_5b): Move
	closing } to the same line as the call to work-around differences in
	diagnostics line.