Merge pull request #590 from RalfJung/check-bounds

add test for offseting fn ptr

tests/run-pass/ptr_offset.rs

@@ -1,6 +1,16 @@
+fn f() -> i32 { 42 }
+
 fn main() {
     let v = [1i16, 2];
     let x = &v as *const i16;
     let x = unsafe { x.offset(1) };
     assert_eq!(unsafe { *x }, 2);
+
+    // fn ptr offset
+    unsafe {
+        let p = f as fn() -> i32 as usize;
+        let x = (p as *mut u32).offset(0) as usize;
+        let f: fn() -> i32 = std::mem::transmute(x);
+        assert_eq!(f(), 42);
+    }
 }