Hi Tobias, On Fri, 11 Apr 2014 16:04:51, Tobias Burnus wrote: > > Hi Tobias, > > On Fri, Apr 11, 2014 at 02:39:57PM +0200, Bernd Edlinger wrote: >> On Fri, 11 Apr 2014 13:37:46, Tobias Burnus wrote: >> Hmm, >> >> I was hoping somehow that only that test case is broken, >> and needs to be fixed. The target attribute is somehow simple, >> it implies intent(in) and the actual value will in most cases >> be a pointer, as in the example. > > I think that passing another nonpointer TARGET to a dummy argument > which has a TARGET attribute is at least as common as passing a > POINTER to a TARGET. > > TARGET is roughtly the opposite to the restrict qualifier. By default > any nonpointer variable does not alias with something else, unless > it has the TARGET attribute; if it has, it (its address) can then > be assigned to a pointer. POINTER intrinsically alias and cannot > have the TARGET attribute. > >>> Pointer -> Nonalloc >>> Allocatable -> Noalloc >>> Nonallocatable*/Allocatable* -> Pointer with intent(in) >> >> Well, this approach does not handle intent(inout) at all. > >
Now I have created a test case for the different aliasing issues
with may arise with scalar objects.
As you pointed out, also conversions of allocatable -> nonalloc,
allocatable -> pointer and nonalloc -> pointer turn out to
violate the strict aliasing rules. However, conversions of
arrays of objects with different attributes seem to be safe.
I have not been able to find an example where it would be
necessary to write the modified class object back to the original
location. But I am not really a Fortran expert.
Unfortunately there are also conversions of optional allocatable ->
optional pointer, which complicate the whole thing quite a lot.
I have found these in class_optional_2.f90.
Boot-strapped and regression-tested on x86_64-linux-gnu.
OK for trunk?
Thanks
Bernd.
2014-04-15 Bernd Edlinger <bernd.edlin...@hotmail.de>
PR fortran/60718
* trans-expr.c (gfc_conv_procedure_call): Fix a strict aliasing
violation when passing a class object to a formal parameter which has
different pointer or allocatable attributes.
patch-pr60718.diff
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