[PATCH] Fortran: Fix incompatible types between INTEGER(8) and TYPE(c_ptr)

[Paul-Antoine Arras <pa@codesourcery.com>]

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Hi all,

The attached patch fixes a bug that causes valid OpenMP declare variant 
directive and functions to be rejected with the following error (see 
testcase):

c_ptr.f90:41:37:

    41 |     !$omp declare variant(foo_variant)          &
       |                                     1
Error: variant ‘foo_variant’ and base ‘foo’ at (1) have incompatible 
types: Type mismatch in argument 'c_bv' (INTEGER(8)/TYPE(c_ptr))

The fix consists in special-casing this situation in gfc_compare_types().

OK for mainline?

Thanks,
-- 
PA

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From 8e5fa4828678a1388e75795de2a1f253d9f0ec95 Mon Sep 17 00:00:00 2001
From: Paul-Antoine Arras <pa@codesourcery.com>
Date: Fri, 20 Oct 2023 12:42:49 +0200
Subject: [PATCH] Fortran: Fix incompatible types between INTEGER(8) and
 TYPE(c_ptr)

In the context of an OpenMP declare variant directive, arguments of type C_PTR
are sometimes recognised as C_PTR in the base function and as INTEGER(8) in the
variant - or the other way around, depending on the parsing order.
This patch prevents such situation from turning into a compile error.

2023-10-20  Paul-Antoine Arras  <pa@codesourcery.com>
	    Tobias Burnus  <tobias@codesourcery.com>

gcc/fortran/ChangeLog:

	* interface.cc (gfc_compare_types): Return true in this situation.

gcc/testsuite/ChangeLog:

	* gfortran.dg/c_ptr_tests_20.f90: New test.
---
 gcc/fortran/ChangeLog.omp                    |  5 ++
 gcc/fortran/interface.cc                     | 17 +++---
 gcc/testsuite/ChangeLog.omp                  |  4 ++
 gcc/testsuite/gfortran.dg/c_ptr_tests_20.f90 | 56 ++++++++++++++++++++
 4 files changed, 76 insertions(+), 6 deletions(-)
 create mode 100644 gcc/testsuite/gfortran.dg/c_ptr_tests_20.f90

diff --git a/gcc/fortran/ChangeLog.omp b/gcc/fortran/ChangeLog.omp
index 62a33475ee5..299223ceaa7 100644
--- a/gcc/fortran/ChangeLog.omp
+++ b/gcc/fortran/ChangeLog.omp
@@ -1,3 +1,8 @@
+2023-10-20  Paul-Antoine Arras  <pa@codesourcery.com>
+	    Tobias Burnus  <tobias@codesourcery.com>
+
+	* interface.cc (gfc_compare_types): Return true in this situation.
+
 2023-09-19  Tobias Burnus  <tobias@codesourcery.com>
 
 	Backported from master:
diff --git a/gcc/fortran/interface.cc b/gcc/fortran/interface.cc
index e9843e9549c..8bd35fd6d22 100644
--- a/gcc/fortran/interface.cc
+++ b/gcc/fortran/interface.cc
@@ -705,12 +705,17 @@ gfc_compare_types (gfc_typespec *ts1, gfc_typespec *ts2)
 
   /* Special case for our C interop types.  FIXME: There should be a
      better way of doing this.  When ISO C binding is cleared up,
-     this can probably be removed.  See PR 57048.  */
-
-  if (((ts1->type == BT_INTEGER && ts2->type == BT_DERIVED)
-       || (ts1->type == BT_DERIVED && ts2->type == BT_INTEGER))
-      && ts1->u.derived && ts2->u.derived
-      && ts1->u.derived == ts2->u.derived)
+     this can probably be removed.  See PR 57048.
+     Note that this does not distinguish between c_ptr and c_funptr.  */
+
+  if ((ts1->type == BT_INTEGER && ts2->type == BT_DERIVED
+       && ts1->f90_type == BT_VOID
+       && ts2->u.derived->ts.is_iso_c
+       && ts2->u.derived->ts.u.derived->ts.f90_type == BT_VOID)
+      || (ts2->type == BT_INTEGER && ts1->type == BT_DERIVED
+	  && ts2->f90_type == BT_VOID
+	  && ts1->u.derived->ts.is_iso_c
+	  && ts1->u.derived->ts.u.derived->ts.f90_type == BT_VOID))
     return true;
 
   /* The _data component is not always present, therefore check for its
diff --git a/gcc/testsuite/ChangeLog.omp b/gcc/testsuite/ChangeLog.omp
index e9f4d1c63e6..1fc9b0606dc 100644
--- a/gcc/testsuite/ChangeLog.omp
+++ b/gcc/testsuite/ChangeLog.omp
@@ -1,3 +1,7 @@
+2023-10-20  Paul-Antoine Arras  <pa@codesourcery.com>
+
+	* gfortran.dg/c_ptr_tests_20.f90: New test.
+
 2023-09-20  Tobias Burnus  <tobias@codesourcery.com>
 
 	Backported from master:
diff --git a/gcc/testsuite/gfortran.dg/c_ptr_tests_20.f90 b/gcc/testsuite/gfortran.dg/c_ptr_tests_20.f90
new file mode 100644
index 00000000000..777181cece0
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/c_ptr_tests_20.f90
@@ -0,0 +1,56 @@
+! { dg-do compile }
+!
+! This failed to compile the declare variant directive due to the C_PTR 
+! arguments to foo being recognised as INTEGER(8)
+
+program adjust_args
+  use iso_c_binding, only: c_loc
+  implicit none
+
+  integer, parameter :: N = 1024
+  real, allocatable, target :: av(:), bv(:), cv(:)
+
+  call foo(c_loc(bv), c_loc(av), N)
+
+  !$omp target data map(to: av(:N)) map(from: cv(:N))
+      !$omp parallel
+      call foo(c_loc(cv), c_loc(av), N)
+      !$omp end parallel
+  !$omp end target data
+    
+contains
+  subroutine foo_variant(c_d_bv, c_d_av, n)
+    use iso_c_binding, only: c_ptr, c_f_pointer
+    type(c_ptr), intent(in) :: c_d_bv, c_d_av
+    integer, intent(in) :: n
+    real, pointer :: f_d_bv(:)
+    real, pointer :: f_d_av(:)
+    integer :: i
+  
+    call c_f_pointer(c_d_bv, f_d_bv, [n])
+    call c_f_pointer(c_d_av, f_d_av, [n])
+    !$omp target teams loop is_device_ptr(f_d_bv, f_d_av)
+    do i = 1, n
+      f_d_bv(i) = f_d_av(i) * i
+    end do
+  end subroutine
+  
+  
+  subroutine foo(c_bv, c_av, n)
+    use iso_c_binding, only: c_ptr, c_f_pointer
+    type(c_ptr), intent(in) :: c_bv, c_av
+    integer, intent(in) :: n
+    real, pointer :: f_bv(:)
+    real, pointer :: f_av(:)
+    integer :: i
+    !$omp declare variant(foo_variant)          &
+    !$omp         match(construct={parallel})       
+  
+    call c_f_pointer(c_bv, f_bv, [n])
+    call c_f_pointer(c_av, f_av, [n])
+    !$omp parallel loop
+    do i = 1, n
+      f_bv(i) = f_av(i) * i
+    end do
+  end subroutine
+end program
-- 
2.42.0