[gcc r13-3342] Fortran: NULL pointer dereference in gfc_simplify_image_index [PR104330]

[Harald Anlauf <anlauf@gcc.gnu.org>]

https://gcc.gnu.org/g:84807af0ca6dfdb81abb8e925ce32acbcab29868

commit r13-3342-g84807af0ca6dfdb81abb8e925ce32acbcab29868
Author: Steve Kargl <kargl@gcc.gnu.org>
Date:   Mon Oct 17 22:42:40 2022 +0200

    Fortran: NULL pointer dereference in gfc_simplify_image_index [PR104330]
    
    gcc/fortran/ChangeLog:
    
            PR fortran/104330
            * simplify.cc (gfc_simplify_image_index): Do not dereference NULL
            pointer.
    
    gcc/testsuite/ChangeLog:
    
            PR fortran/104330
            * gfortran.dg/pr104330.f90: New test.

Diff:
---
 gcc/fortran/simplify.cc                |  2 +-
 gcc/testsuite/gfortran.dg/pr104330.f90 | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/gcc/fortran/simplify.cc b/gcc/fortran/simplify.cc
index 6ac92cf9db8..9c2fea8c5f2 100644
--- a/gcc/fortran/simplify.cc
+++ b/gcc/fortran/simplify.cc
@@ -8266,7 +8266,7 @@ gfc_simplify_image_index (gfc_expr *coarray, gfc_expr *sub)
     if (ref->type == REF_COMPONENT)
       as = ref->u.ar.as;
 
-  if (as->type == AS_DEFERRED)
+  if (!as || as->type == AS_DEFERRED)
     return NULL;
 
   /* "valid sequence of cosubscripts" are required; thus, return 0 unless
diff --git a/gcc/testsuite/gfortran.dg/pr104330.f90 b/gcc/testsuite/gfortran.dg/pr104330.f90
new file mode 100644
index 00000000000..9ff48e2f6cc
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr104330.f90
@@ -0,0 +1,20 @@
+! { dg-do compile }
+! { dg-options "-fcoarray=lib" }
+!
+! PR fortran/104330 - ICE in gfc_simplify_image_index
+! Contributed by G.Steinmetz
+
+program p
+  implicit none
+  type t
+  end type t
+  class(*), allocatable :: x[:]
+  class(t), allocatable :: y[:]
+  type(t),  allocatable :: z[:]
+  allocate (real :: x[*])
+  print *, image_index(x, [1])
+  allocate (t :: y[*])
+  print *, image_index(y, [1])
+  allocate (t :: z[*])
+  print *, image_index(z, [1])
+end