From 2b75d5f533b9d6b39f4055949aff64ed0d22dd24 Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anlauf@gmx.de>
Date: Thu, 15 Sep 2022 22:39:24 +0200
Subject: [PATCH] Fortran: catch NULL pointer dereferences while simplifying
 PACK [PR106857]

gcc/fortran/ChangeLog:

	PR fortran/106857
	* simplify.cc (gfc_simplify_pack): Check for NULL pointer dereferences
	while walking through constructors (error recovery).

gcc/testsuite/ChangeLog:

	PR fortran/106857
	* gfortran.dg/pr106857.f90: New test.
---
 gcc/fortran/simplify.cc                |  2 +-
 gcc/testsuite/gfortran.dg/pr106857.f90 | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gfortran.dg/pr106857.f90

diff --git a/gcc/fortran/simplify.cc b/gcc/fortran/simplify.cc
index bc178d54891..140c17721a7 100644
--- a/gcc/fortran/simplify.cc
+++ b/gcc/fortran/simplify.cc
@@ -6431,7 +6431,7 @@ gfc_simplify_pack (gfc_expr *array, gfc_expr *mask, gfc_expr *vector)
       /* Copy only those elements of ARRAY to RESULT whose
 	 MASK equals .TRUE..  */
       mask_ctor = gfc_constructor_first (mask->value.constructor);
-      while (mask_ctor)
+      while (mask_ctor && array_ctor)
 	{
 	  if (mask_ctor->expr->value.logical)
 	    {
diff --git a/gcc/testsuite/gfortran.dg/pr106857.f90 b/gcc/testsuite/gfortran.dg/pr106857.f90
new file mode 100644
index 00000000000..4b0f86a75a6
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr106857.f90
@@ -0,0 +1,12 @@
+! { dg-do compile }
+! PR fortran/106857 - ICE in gfc_simplify_pack
+! Contributed by G.Steinmetz
+
+program p
+  type t
+     integer :: n
+  end type
+  type(t), parameter :: a(2,2) = t(1)
+  type(t), parameter :: b(4) = reshape(a, [2])                          ! { dg-error "Different shape" }
+  type(t), parameter :: c(2) = pack(b, [.false.,.true.,.false.,.true.]) ! { dg-error "Different shape" }
+end
--
2.35.3