[gcc(refs/users/mikael/heads/refactor_descriptor_v206.01)] fortran: array descriptor: Don't set the span in the scalar case [PR122521]

https://gcc.gnu.org/g:646598d2a4f941d382e32538dc55d666db7f75c7

commit 646598d2a4f941d382e32538dc55d666db7f75c7
Author: Mikael Morin <[email protected]>
Date:   Mon Aug 10 21:40:12 2026 +0200

    fortran: array descriptor: Don't set the span in the scalar case [PR122521]
    
    Fortran-tested on aarch64-unknown-linux-gnu.  OK for mainline?
    
    -- >8 --
    
    The span in an array descriptor is a multiplier of the stride representing
    the address difference between two consecutive array elements.  For scalar
    descriptors, there is a single element, so it can't be used in any useful
    way.
    
    This patch removes the initialization of the span of descriptors in the
    scalar case.
    
    One additional tweak is required to avoid regressing.  In the library
    implementation of the ASSOCIATED intrinsic, the two descriptors are checked
    to have the same span, assuming the span to be always set.  Make that check
    conditional on the rank being non-zero.
    
            PR fortran/122521
    
    gcc/fortran/ChangeLog:
    
            * trans-descriptor.cc (gfc_set_descriptor_from_scalar): Remove
            descriptor span initialization.
    
    libgfortran/ChangeLog:
    
            * intrinsics/associated.c (associated): Only compare spans if
            the rank is non-zero.
    
    gcc/testsuite/ChangeLog:
    
            * gfortran.dg/coarray_collectives_18.f90: Update pattern count.

Diff:
---
 gcc/fortran/trans-descriptor.cc                      | 2 --
 gcc/testsuite/gfortran.dg/coarray_collectives_18.f90 | 2 +-
 libgfortran/intrinsics/associated.c                  | 5 +++--
 3 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/gcc/fortran/trans-descriptor.cc b/gcc/fortran/trans-descriptor.cc
index 6ec9593c3b7b..a7739355d4cb 100644
--- a/gcc/fortran/trans-descriptor.cc
+++ b/gcc/fortran/trans-descriptor.cc
@@ -880,8 +880,6 @@ gfc_set_descriptor_from_scalar (stmtblock_t *block, tree descr, tree scalar)
   gfc_conv_descriptor_dtype_set (block, descr,
 				 gfc_get_dtype_rank_type (0, etype));
   gfc_conv_descriptor_data_set (block, descr, scalar);
-  gfc_conv_descriptor_span_set (block, descr,
-				gfc_conv_descriptor_elem_len_get (descr));
 }
 
 
diff --git a/gcc/testsuite/gfortran.dg/coarray_collectives_18.f90 b/gcc/testsuite/gfortran.dg/coarray_collectives_18.f90
index c83899de0e5b..5636a89e94a9 100644
--- a/gcc/testsuite/gfortran.dg/coarray_collectives_18.f90
+++ b/gcc/testsuite/gfortran.dg/coarray_collectives_18.f90
@@ -33,5 +33,5 @@ end program
 ! This lead to access to non exsitant memory in opencoarrays.
 ! In single image mode just checking for reduced number of
 ! descriptors is possible, i.e., execute always works.
-! { dg-final { scan-tree-dump-times "desc\\.\[0-9\]+" 12 "original" } }
+! { dg-final { scan-tree-dump-times "desc\\.\[0-9\]+" 8 "original" } }
 
diff --git a/libgfortran/intrinsics/associated.c b/libgfortran/intrinsics/associated.c
index fecc1b3a2832..b597b862d031 100644
--- a/libgfortran/intrinsics/associated.c
+++ b/libgfortran/intrinsics/associated.c
@@ -37,13 +37,14 @@ associated (const gfc_array_void *pointer, const gfc_array_void *target)
     return 0;
   if (GFC_DESCRIPTOR_DATA (pointer) != GFC_DESCRIPTOR_DATA (target))
     return 0;
-  if (GFC_DESCRIPTOR_SPAN (pointer) != GFC_DESCRIPTOR_SPAN (target))
-    return 0;
   if (GFC_DESCRIPTOR_DTYPE (pointer).type != GFC_DESCRIPTOR_DTYPE (target).type)
     return 0;
   rank = GFC_DESCRIPTOR_RANK (pointer);
   if (rank != GFC_DESCRIPTOR_RANK (target))
     return 0;
+  if (rank != 0
+      && GFC_DESCRIPTOR_SPAN (pointer) != GFC_DESCRIPTOR_SPAN (target))
+    return 0;
   for (n = 0; n < rank; n++)
     {
       long extent;