[PATCH] Fortran: error recovery simplifying UNPACK for insufficient FIELD [PR107922]

[Harald Anlauf <anlauf@gmx.de>]

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Dear all,

we did not properly handle the case of insufficient array-valued
FIELD when trying to simplify UNPACK and could run into a NULL
pointer dereference.  The fix is obvious.

Regtested on x86_64-pc-linux-gnu.  OK for mainline?

Thanks,
Harald


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From 0ff50e73c6fce52263b9530daffe6743c1fc9b2c Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anlauf@gmx.de>
Date: Thu, 1 Dec 2022 21:16:46 +0100
Subject: [PATCH] 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.
---
 gcc/fortran/simplify.cc                      |  9 ++++++++-
 gcc/testsuite/gfortran.dg/unpack_field_1.f90 | 15 +++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gfortran.dg/unpack_field_1.f90

diff --git a/gcc/fortran/simplify.cc b/gcc/fortran/simplify.cc
index b6184181f26..0a0a7755f4c 100644
--- a/gcc/fortran/simplify.cc
+++ b/gcc/fortran/simplify.cc
@@ -8485,7 +8485,14 @@ 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
--
2.35.3