diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 42f417abb27..caa854d5a43 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2020-03-04  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/94001
+	* tree-tailcall.c (process_assignment): Before comparing op1 to
+	*ass_var, verify *ass_var is non-NULL.
+
 2020-03-04  Kito Cheng  <kito.cheng@sifive.com>
 
 	PR target/93995
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index cd519f4116b..a13a0a4ba59 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-03-04  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/94001
+	* gcc.dg/pr94001.c: New test.
+
 2020-03-04  Kito Cheng  <kito.cheng@sifive.com>
 
 	PR target/93995
diff --git a/gcc/testsuite/gcc.dg/pr94001.c b/gcc/testsuite/gcc.dg/pr94001.c
new file mode 100644
index 00000000000..f83873fa2bd
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr94001.c
@@ -0,0 +1,11 @@
+/* PR tree-optimization/94001 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-tree-dce" } */
+
+void
+bar (int e)
+{
+  bar (3);
+  int c;
+  c = -e;
+}
diff --git a/gcc/tree-tailcall.c b/gcc/tree-tailcall.c
index 9ffe739f601..d81e9213460 100644
--- a/gcc/tree-tailcall.c
+++ b/gcc/tree-tailcall.c
@@ -339,7 +339,8 @@ process_assignment (gassign *stmt,
 	   && (non_ass_var = independent_of_stmt_p (op1, stmt, call,
 						    to_move)))
     ;
-  else if (op1 == *ass_var
+  else if (*ass_var
+	   && op1 == *ass_var
 	   && (non_ass_var = independent_of_stmt_p (op0, stmt, call,
 						    to_move)))
     ;