PING please
On 7/30/26 10:21 AM, Jerry D wrote:
See the attached patch.
As stated in the PR we were missing the stride multiplier (ie span)
I will note as a useful tool: I had an initial patch for this but wanted
to exercise it. I prompted Claude Pro Opus 5 to create numerous
variations on the original test case provided by Tobias Burnus in the
original report. The result was 25 to 30 variations which were helpful
in identifying code paths I would not have otherwise found. I am not
using those test cases here.
I flagged out this one to work on as it has been around a long time and
we were giving wrong results without any idea it was happening.
I also wanted to mention that the fortran standardese is difficult to
interpret but I think I got this right.
Regression tested on x86_64.
OK for mainline?
Comments appreciated.
Regards,
Jerry
---
fortran: [PR53800] Wrong copy-in/out with CLASS array to assumed-
shape TYPE
A CLASS array actual passed to a plain assumed-shape derived-type
dummy
was always copied in and out, so pointers associated with the dummy
went
stale on return. F2023 15.5.2.5 paragraph 9 requires the dummy to be
associated with the actual's storage when it has the TARGET
attribute and
lacks CONTIGUOUS and VALUE; paragraph 8 leaves every other case
free to
use a copy. Pass such a dummy by reference and address its
elements with
the descriptor's runtime span.
PR fortran/53800
gcc/fortran/ChangeLog:
* trans-array.cc (need_span): New function.
(gfc_get_array_span): Read the span from the saved
descriptor of a
span-array dummy, but not for a sub-array reached through a
component.
(gfc_conv_scalarized_array_ref): Use need_span.
(gfc_conv_array_ref): Likewise.
(build_array_ref): Default DECL to DESC for a span-array decl.
* trans-decl.cc (gfc_build_dummy_array_decl): Mark a TARGET
assumed-shape derived-type dummy as needing runtime span
addressing, unless it is repacked.
* trans-expr.cc (class_actual_aliases_type_dummy): New
function.
(gfc_class_array_data_assign): Also copy the span field.
(gfc_conv_procedure_call): Use
class_actual_aliases_type_dummy to
skip copy-in/copy-out for both the class array reference
and the
class array function actual argument.
* trans.cc (get_array_span): Read the span from the dummy's
saved
descriptor for span-array decls.
* trans.h (struct lang_decl): Add span_array bitfield.
(GFC_DECL_SPAN_ARRAY_P): New macro.
(GFC_DECL_GET_SPAN_ARRAY_P): New macro.
gcc/testsuite/ChangeLog:
* gfortran.dg/class_to_type_5.f90: New test.
* gfortran.dg/class_to_type_6.f90: New test.
