diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7c757c0ef41..08a0c08946d 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2018-08-24  Segher Boessenkool  <segher@kernel.crashing.org>
+
+	PR target/86989
+	* config/rs6000/rs6000.c (toc_relative_expr_p): Check that the base is
+	the TOC register.
+
 2018-08-24  Aldy Hernandez  <aldyh@redhat.com>
 
 	PR 87073/bootstrap
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 252d197a746..ecaf0718ca7 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -7943,7 +7943,9 @@ toc_relative_expr_p (const_rtx op, bool strict, const_rtx *tocrel_base_ret,
     *tocrel_offset_ret = tocrel_offset;
 
   return (GET_CODE (tocrel_base) == UNSPEC
-	  && XINT (tocrel_base, 1) == UNSPEC_TOCREL);
+	  && XINT (tocrel_base, 1) == UNSPEC_TOCREL
+	  && REG_P (XVECEXP (tocrel_base, 0, 1))
+	  && REGNO (XVECEXP (tocrel_base, 0, 1)) == TOC_REGISTER);
 }
 
 /* Return true if X is a constant pool address, and also for cmodel=medium