--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/prefetch-loop-arrays-1.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,36 @@
+/* PR tree-optimization/28887 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fprefetch-loop-arrays -w" } */
+/* { dg-options "-O2 -fprefetch-loop-arrays -march=i686 -msse -w" { target { { i?86-*-* x86_64-*-* } && ia32 } } } */
+
+__extension__ typedef __SIZE_TYPE__ size_t;
+
+struct re_pattern_buffer
+{
+  size_t re_nsub;
+};
+
+typedef enum
+{
+  start_memory,
+} re_opcode_t;
+
+typedef union
+{
+  struct
+  {
+    unsigned matched_something:1;
+  } bits;
+} byte_register_info_type;
+
+void byte_re_match_2_internal (struct re_pattern_buffer *bufp)
+{
+  int mcnt;
+  size_t num_regs = bufp->re_nsub + 1;
+  byte_register_info_type *reg_info;
+  for (mcnt = 1; (unsigned) mcnt < num_regs; mcnt++)
+    {
+      ((reg_info[mcnt]).bits.matched_something) = 0;
+    }
+}
+