1 files changed, 60 insertions, 0 deletions
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/prefetch-5.c b/gcc/testsuite/gcc.dg/tree-ssa/prefetch-5.c
new file mode 100644
index 000000000..19914cabf
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/prefetch-5.c
@@ -0,0 +1,60 @@
+/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
+/* { dg-require-effective-target ilp32 } */
+/* { dg-options "-O2 --param min-insn-to-prefetch-ratio=5 -fprefetch-loop-arrays -march=athlon -fdump-tree-aprefetch-details" } */
+
+/* These are common idioms for writing variable-length arrays at the end
+   of structures.  We should not deduce anything about the number of iterations
+   of the loops from them.  */
+
+struct tail0
+{
+  int xxx;
+  int yyy[0];
+};
+
+int loop0 (int n, struct tail0 *x)
+{
+  int i, s = 0;
+
+  for (i = 0; i < n; i++)
+    s += x->yyy[i];
+
+  return s;
+}
+
+struct tail1
+{
+  int xxx;
+  int yyy[1];
+};
+int loop1 (int n, struct tail1 *x)
+{
+  int i, s = 0;
+
+  for (i = 0; i < n; i++)
+    s += x->yyy[i];
+
+  return s;
+}
+
+/* It is unlikely that this should be a tail array.  We may deduce that most
+   likely, the loop iterates about 5 times, and the array is not worth prefetching.  */
+
+struct tail5
+{
+  int xxx;
+  int yyy[5];
+};
+int loop5 (int n, struct tail5 *x)
+{
+  int i, s = 0;
+
+  for (i = 0; i < n; i++)
+    s += x->yyy[i];
+
+  return s;
+}
+
+/* { dg-final { scan-tree-dump-times "Issued prefetch" 2 "aprefetch" } } */
+/* { dg-final { scan-tree-dump-times "Not prefetching" 1 "aprefetch" } } */
+/* { dg-final { cleanup-tree-dump "aprefetch" } } */