1 files changed, 25 insertions, 0 deletions
diff --git a/gcc/testsuite/g++.dg/opt/alias1.C b/gcc/testsuite/g++.dg/opt/alias1.C
new file mode 100644
index 000000000..4836c5be0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/opt/alias1.C
@@ -0,0 +1,25 @@
+// Test that type punning using an anonymous union works with strict aliasing.
+// { dg-do run }
+// { dg-options "-O2 -fstrict-aliasing" }
+
+extern "C" void abort ();
+
+void f (long i)
+{
+  union
+  {
+    long ui;
+    float uf[20];
+  };
+
+  ui = i;
+  if (uf[0] != 42.0)
+    abort ();
+}
+
+int main ()
+{
+  union U { long i; float f[20]; } u;
+  u.f[0] = 42.0;
+  f (u.i);
+}