diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 9536e0a73d8..7f2a5ae51e7 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2010-12-18  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/46985
+	* tree-scalar-evolution.c (instantiate_scev_r): If chrec is NULL,
+	return it immediately.
+
 2010-12-18  John David Anglin  <dave.anglin@nrc-cnrc.gc.ca>
 
 	PR target/46915
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 64b9ffece4e..711f3437e74 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2010-12-18  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/46985
+	* gfortran.dg/pr46985.f90: New test.
+
 2010-12-18  Eric Botcazou  <ebotcazou@adacore.com>
 
 	PR tree-optimization/46232
diff --git a/gcc/testsuite/gfortran.dg/pr46985.f90 b/gcc/testsuite/gfortran.dg/pr46985.f90
new file mode 100644
index 00000000000..141641d29e9
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr46985.f90
@@ -0,0 +1,17 @@
+! PR tree-optimization/46985
+! { dg-do compile }
+! { dg-options "-O -ftree-pre -ftree-vrp -fno-tree-ccp -fno-tree-dominator-opts -fno-tree-fre" }
+
+  type :: t
+    integer :: i
+  end type t
+  type(t), target :: tar(2) = (/t(2), t(4)/)
+  integer, pointer :: ptr(:)
+  ptr => tar%i
+  call foo (ptr)
+contains
+  subroutine foo (arg)
+    integer :: arg(:)
+    arg = arg - 1
+  end subroutine
+end
diff --git a/gcc/tree-scalar-evolution.c b/gcc/tree-scalar-evolution.c
index 4a4bda9d925..24be2e8c26f 100644
--- a/gcc/tree-scalar-evolution.c
+++ b/gcc/tree-scalar-evolution.c
@@ -2616,7 +2616,8 @@ instantiate_scev_r (basic_block instantiate_below,
   if (size_expr++ > PARAM_VALUE (PARAM_SCEV_MAX_EXPR_SIZE))
     return chrec_dont_know;
 
-  if (automatically_generated_chrec_p (chrec)
+  if (chrec == NULL_TREE
+      || automatically_generated_chrec_p (chrec)
       || is_gimple_min_invariant (chrec))
     return chrec;