Hi Harald,
Thanks for your help, please see the updated and signed-off patch below.
> (I am not entirely sure whether we need to exclude pointer and
> allocatable attributes here explicitly, given the constraints
> in F2023:15.5.2.6, but other may have an opinion, too.
> The above should be safe anyway.)
I've included them in the patch here, but it does seem to work fine
without checking those attributes here -- and invalid code is still
caught with that change.
It also occurred to me that array temporaries aren't _required_ here
(for arrays of derived type components), but in the general case with
a type with differently sized components, the stride wouldn't be a
multiple of the component's type's size. Is it possible in principle
to have an arbitrary stride?
Cheers,
Peter
>From 907a104facfc7f35f48ebcfa9ef5f8f5430d4d3c Mon Sep 17 00:00:00 2001
From: Peter Hill <peter.h...@york.ac.uk>
Date: Thu, 15 Feb 2024 16:58:33 +0000
Subject: [PATCH] Fortran: fix passing array component ref to polymorphic
procedures
PR fortran/105658
gcc/fortran/ChangeLog
* trans-expr.cc (gfc_conv_intrinsic_to_class): When passing an
array component reference of intrinsic type to a procedure
with an unlimited polymorphic dummy argument, a temporary
should be created.
gcc/testsuite/ChangeLog
* gfortran.dg/PR105658.f90: New test.
Signed-off-by: Peter Hill <peter.h...@york.ac.uk>
---
gcc/fortran/trans-expr.cc | 9 +++++
gcc/testsuite/gfortran.dg/PR105658.f90 | 50 ++++++++++++++++++++++++++
2 files changed, 59 insertions(+)
create mode 100644 gcc/testsuite/gfortran.dg/PR105658.f90
diff --git a/gcc/fortran/trans-expr.cc b/gcc/fortran/trans-expr.cc
index a0593b76f18..004081aa6c3 100644
--- a/gcc/fortran/trans-expr.cc
+++ b/gcc/fortran/trans-expr.cc
@@ -1019,6 +1019,14 @@ gfc_conv_intrinsic_to_class (gfc_se *parmse, gfc_expr *e,
tmp = gfc_typenode_for_spec (&class_ts);
var = gfc_create_var (tmp, "class");
+ /* Force a temporary for component or substring references */
+ if (unlimited_poly
+ && class_ts.u.derived->components->attr.dimension
+ && !class_ts.u.derived->components->attr.allocatable
+ && !class_ts.u.derived->components->attr.class_pointer
+ && is_subref_array (e))
+ parmse->force_tmp = 1;
+
/* Set the vptr. */
ctree = gfc_class_vptr_get (var);
@@ -6439,6 +6447,7 @@ gfc_conv_procedure_call (gfc_se * se, gfc_symbol * sym,
CLASS object for the unlimited polymorphic formal. */
gfc_find_vtab (&e->ts);
gfc_init_se (&parmse, se);
+
gfc_conv_intrinsic_to_class (&parmse, e, fsym->ts);
}
diff --git a/gcc/testsuite/gfortran.dg/PR105658.f90
b/gcc/testsuite/gfortran.dg/PR105658.f90
new file mode 100644
index 00000000000..8aacecf806e
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/PR105658.f90
@@ -0,0 +1,50 @@
+! { dg-do compile }
+! { dg-options "-Warray-temporaries" }
+! Test fix for incorrectly passing array component to unlimited
polymorphic procedure
+
+module test_PR105658_mod
+ implicit none
+ type :: foo
+ integer :: member1
+ integer :: member2
+ end type foo
+contains
+ subroutine print_poly(array)
+ class(*), dimension(:), intent(in) :: array
+ select type(array)
+ type is (integer)
+ print*, array
+ type is (character(*))
+ print *, array
+ end select
+ end subroutine print_poly
+
+ subroutine do_print(thing)
+ type(foo), dimension(3), intent(in) :: thing
+ type(foo), parameter :: y(3) = [foo(1,2),foo(3,4),foo(5,6)]
+ integer :: i, j, uu(5,6)
+
+ call print_poly(thing%member1) ! { dg-warning "array temporary" }
+ call print_poly(y%member2) ! { dg-warning "array temporary" }
+ call print_poly(y(1::2)%member2) ! { dg-warning "array temporary" }
+
+ ! The following array sections work without temporaries
+ uu = reshape([(((10*i+j),i=1,5),j=1,6)],[5,6])
+ print *, uu(2,2::2)
+ call print_poly (uu(2,2::2)) ! no temp needed!
+ print *, uu(1::2,6)
+ call print_poly (uu(1::2,6)) ! no temp needed!
+ end subroutine do_print
+
+ subroutine do_print2(thing2)
+ class(foo), dimension(:), intent(in) :: thing2
+ call print_poly (thing2% member2) ! { dg-warning "array temporary" }
+ end subroutine do_print2
+
+ subroutine do_print3 ()
+ character(3) :: c(3) = ["abc","def","ghi"]
+ call print_poly (c(1::2)) ! no temp needed!
+ call print_poly (c(1::2)(2:3)) ! { dg-warning "array temporary" }
+ end subroutine do_print3
+
+end module test_PR105658_mod
--
2.43.0
