diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 8471e8a01f4..83a6f3cc566 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2016-05-20  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/71185
+	* tree-ssa-loop-prefetch.c (gather_memory_references): Drop
+	register operations.
+
 2016-05-20  Richard Biener  <rguenther@suse.de>
 
 	* tree-if-conv.c (add_bb_predicate_gimplified_stmts): Use
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 0c2f4bc2dfe..87588f02129 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2016-05-20  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/71185
+	* gcc.dg/tree-ssa/pr71185.c: New testcase.
+
 2016-05-20  Richard Biener  <rguenther@suse.de>
 
 	* gcc.dg/tree-ssa/ifc-cd.c: Adjust.
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr71185.c b/gcc/testsuite/gcc.dg/tree-ssa/pr71185.c
new file mode 100644
index 00000000000..c2e246f1cd0
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr71185.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-options "-O3" } */
+/* { dg-options "-O3 -march=barcelona" { target x86_64-*-* i?86-*-* } } */
+
+union U { struct S { int l; int m; } p; long long a; } b;
+int a, c;
+
+void
+foo ()
+{
+  for (; b.p.m; b.a += c)
+    a = b.p.l / 65536.0 * 65536.0;
+}
diff --git a/gcc/tree-ssa-loop-prefetch.c b/gcc/tree-ssa-loop-prefetch.c
index 49fd597a892..fb8c4763769 100644
--- a/gcc/tree-ssa-loop-prefetch.c
+++ b/gcc/tree-ssa-loop-prefetch.c
@@ -631,6 +631,9 @@ gather_memory_references (struct loop *loop, bool *no_other_refs, unsigned *ref_
 	      continue;
 	    }
 
+	  if (! gimple_vuse (stmt))
+	    continue;
+
 	  lhs = gimple_assign_lhs (stmt);
 	  rhs = gimple_assign_rhs1 (stmt);