[gcc r13-4486] Fortran: error recovery simplifying UNPACK for insufficient FIELD [PR107922]

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

https://gcc.gnu.org/g:24b9337d1f1b5197b6498dceb9074319be003449

commit r13-4486-g24b9337d1f1b5197b6498dceb9074319be003449
Author: Harald Anlauf <anlauf@gmx.de>
Date:   Thu Dec 1 21:16:46 2022 +0100

    Fortran: error recovery simplifying UNPACK for insufficient FIELD [PR107922]
    
    gcc/fortran/ChangeLog:
    
            PR fortran/107922
            * simplify.cc (gfc_simplify_unpack): Terminate simplification when
            array-valued argument FIELD does not provide enough elements.
    
    gcc/testsuite/ChangeLog:
    
            PR fortran/107922
            * gfortran.dg/unpack_field_1.f90: New test.

Diff:
---
 gcc/fortran/simplify.cc                      | 11 ++++++++++-
 gcc/testsuite/gfortran.dg/unpack_field_1.f90 | 15 +++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/gcc/fortran/simplify.cc b/gcc/fortran/simplify.cc
index b6184181f26..aff9a1b8ced 100644
--- a/gcc/fortran/simplify.cc
+++ b/gcc/fortran/simplify.cc
@@ -8485,7 +8485,16 @@ gfc_simplify_unpack (gfc_expr *vector, gfc_expr *mask, gfc_expr *field)
 	    }
 	}
       else if (field->expr_type == EXPR_ARRAY)
-	e = gfc_copy_expr (field_ctor->expr);
+	{
+	  if (field_ctor)
+	    e = gfc_copy_expr (field_ctor->expr);
+	  else
+	    {
+	      /* Not enough elements in array FIELD.  */
+	      gfc_free_expr (result);
+	      return &gfc_bad_expr;
+	    }
+	}
       else
 	e = gfc_copy_expr (field);
 
diff --git a/gcc/testsuite/gfortran.dg/unpack_field_1.f90 b/gcc/testsuite/gfortran.dg/unpack_field_1.f90
new file mode 100644
index 00000000000..ca3cfbd2bd4
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/unpack_field_1.f90
@@ -0,0 +1,15 @@
+! { dg-do compile }
+! PR fortran/107922 - ICE in gfc_simplify_unpack
+! Test error recovery when shapes of FIELD and MASK do not match
+! Contributed by G.Steinmetz
+
+program p
+  integer, parameter :: a(2) = 1
+  integer, parameter :: d(3) = 1
+  logical, parameter :: mask(3) = [.false.,.true.,.false.]
+  integer, parameter :: b(2) = unpack(a,mask,a)          ! { dg-error "must have identical shape" }
+  integer :: c(3) = unpack(a,[.false.,.true.,.false.],a) ! { dg-error "must have identical shape" }
+  print *, unpack(a,mask,a)                              ! { dg-error "must have identical shape" }
+  print *, unpack(a,mask,d) ! OK
+  print *, unpack(a,mask,3) ! OK
+end