Workaround issue #152 in _uint.next_power_of_two

Author: froystig

src/Makefile

@@ -491,6 +491,7 @@ TEST_XFAILS_LLVM := $(TASK_XFAILS) \
                       lib-rand.rs \
                       lib-str.rs \
                       lib-task.rs \
+                      lib-uint.rs \
                       lib-vec.rs \
                       lib-vec-str-conversions.rs \
                       linear-for-loop.rs \

src/lib/_uint.rs

@@ -28,7 +28,9 @@ fn next_power_of_two(uint n) -> uint {
   let uint shift = 1u;
   while (shift <= halfbits) {
     tmp |= tmp >> shift;
-    shift <<= 1u;
+    // FIXME (issue #152):  This would be just a tad cuter if it were
+    //   shift <<= 1u
+    shift = shift << 1u;
   }
   ret tmp + 1u;
 }

src/test/run-pass/lib-uint.rs

@@ -0,0 +1,47 @@
+// -*- rust -*-
+
+use std;
+import std._uint;
+
+fn main() {
+  check (_uint.next_power_of_two(0u) == 0u);
+  check (_uint.next_power_of_two(1u) == 1u);
+  check (_uint.next_power_of_two(2u) == 2u);
+  check (_uint.next_power_of_two(3u) == 4u);
+  check (_uint.next_power_of_two(4u) == 4u);
+  check (_uint.next_power_of_two(5u) == 8u);
+  check (_uint.next_power_of_two(6u) == 8u);
+  check (_uint.next_power_of_two(7u) == 8u);
+  check (_uint.next_power_of_two(8u) == 8u);
+  check (_uint.next_power_of_two(9u) == 16u);
+  check (_uint.next_power_of_two(10u) == 16u);
+  check (_uint.next_power_of_two(11u) == 16u);
+  check (_uint.next_power_of_two(12u) == 16u);
+  check (_uint.next_power_of_two(13u) == 16u);
+  check (_uint.next_power_of_two(14u) == 16u);
+  check (_uint.next_power_of_two(15u) == 16u);
+  check (_uint.next_power_of_two(16u) == 16u);
+  check (_uint.next_power_of_two(17u) == 32u);
+  check (_uint.next_power_of_two(18u) == 32u);
+  check (_uint.next_power_of_two(19u) == 32u);
+  check (_uint.next_power_of_two(20u) == 32u);
+  check (_uint.next_power_of_two(21u) == 32u);
+  check (_uint.next_power_of_two(22u) == 32u);
+  check (_uint.next_power_of_two(23u) == 32u);
+  check (_uint.next_power_of_two(24u) == 32u);
+  check (_uint.next_power_of_two(25u) == 32u);
+  check (_uint.next_power_of_two(26u) == 32u);
+  check (_uint.next_power_of_two(27u) == 32u);
+  check (_uint.next_power_of_two(28u) == 32u);
+  check (_uint.next_power_of_two(29u) == 32u);
+  check (_uint.next_power_of_two(30u) == 32u);
+  check (_uint.next_power_of_two(31u) == 32u);
+  check (_uint.next_power_of_two(32u) == 32u);
+  check (_uint.next_power_of_two(33u) == 64u);
+  check (_uint.next_power_of_two(34u) == 64u);
+  check (_uint.next_power_of_two(35u) == 64u);
+  check (_uint.next_power_of_two(36u) == 64u);
+  check (_uint.next_power_of_two(37u) == 64u);
+  check (_uint.next_power_of_two(38u) == 64u);
+  check (_uint.next_power_of_two(39u) == 64u);
+}