Implement the rest of the binary trees shootout benchmark

Author: brson

src/Makefile

@@ -576,6 +576,7 @@ TEST_XFAILS_RUSTC := $(addprefix test/run-pass/, \
                         ), \
                       $(wildcard test/*fail/*.rs test/*fail/*.rc)) \
                      test/bench/shootout/fasta.rs \
+                     test/bench/shootout/binary-trees.rs \
                      $(wildcard test/bench/99-bottles/*rs)
 
 ifdef MINGW_CROSS

src/test/bench/shootout/binary-trees.rs

@@ -1,3 +1,7 @@
+use std;
+
+import std._int;
+
 tag tree {
   nil;
   node(@tree, @tree, int);
@@ -14,5 +18,57 @@ fn item_check(@tree t) -> int {
   }
 }
 
+fn bottom_up_tree(int item, int depth) -> @tree{
+  if (depth > 0) {
+    ret @node(bottom_up_tree(2 * item - 1, depth - 1),
+              bottom_up_tree(2 * item, depth - 1),
+              item);
+  } else {
+    ret @nil;
+  }
+}
+
 fn main() {
+
+  auto n = 8;
+  auto min_depth = 4;
+  auto max_depth;
+  if (min_depth + 2 > n) {
+    max_depth = min_depth + 2;
+  } else {
+    max_depth = n;
+  }
+
+  auto stretch_depth = max_depth + 1;
+
+  auto stretch_tree = bottom_up_tree(0, stretch_depth);
+  log #fmt("stretch tree of depth %d\t check: %d",
+           stretch_depth, item_check(stretch_tree));
+
+  auto long_lived_tree = bottom_up_tree(0, max_depth);
+
+  auto depth = min_depth;
+  while (depth <= max_depth) {
+    auto iterations = _int.pow(2, (max_depth - depth + min_depth) as uint);
+    auto chk = 0;
+
+    auto i = 1;
+    while (i <= iterations) {
+      auto temp_tree = bottom_up_tree(i, depth);
+      chk += item_check(temp_tree);
+
+      temp_tree = bottom_up_tree(-i, depth);
+      chk += item_check(temp_tree);
+
+      i += 1;
+    }
+
+    log #fmt("%d\t trees of depth %d\t check: %d",
+             iterations * 2, depth, chk);
+
+    depth += 2;
+  }
+
+  log #fmt("long lived trees of depth %d\t check: %d",
+           max_depth, item_check(long_lived_tree));
 }