[PATCH, committed] Fortran: catch NULL pointer dereferences while simplifying PACK [PR106857]

[Harald Anlauf <anlauf@gmx.de>]

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Dear all,

we hit a NULL pointer dereference when trying to simplify PACK
when the MASK argument was present.  The obvious and trivial
solution is to check for NULL pointer dereferences why looking
at the constructor for the ARRAY argument, which we already do
in the case the MASK is not present.

Committed to mainline after regtesting on x86_64-pc-linux-gnu
as commit r13-2691-g2b75d5f533b9d6b39f4055949aff64ed0d22dd24

This is a 10/11/12/13 regression, so I will check if it can
be backported.

Thanks,
Harald


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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