Implement graph trimming in ControlReducer.

test/mjsunit/asm/do-while-false.js

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+function Module() {
+  "use asm";
+
+  function d0() {
+    do { } while(false);
+    return 110;
+  }
+
+  function d1() {
+    do { return 111; } while(false);
+    return 112;
+  }
+
+  function d2() {
+    do { break; } while(false);
+    return 113;
+  }
+
+  function d3(a) {
+    a = a | 0;
+    do { if (a) return 114; } while(false);
+    return 115;
+  }
+
+  function d4(a) {
+    a = a | 0;
+    do { if (a) return 116; else break; } while(false);
+    return 117;
+  }
+
+  function d5(a) {
+    a = a | 0;
+    do { if (a) return 118; } while(false);
+    return 119;
+  }
+
+  function d6(a) {
+    a = a | 0;
+    do {
+      if (a == 0) return 120;
+      if (a == 1) break;
+      if (a == 2) return 122;
+      if (a == 3) continue;
+      if (a == 4) return 124;
+    } while(false);
+    return 125;
+  }
+
+  return {d0: d0, d1: d1, d2: d2, d3: d3, d4: d4, d5: d5, d6: d6};
+}
+
+var m = Module();
+
+assertEquals(110, m.d0());
+
+assertEquals(111, m.d1());
+
+assertEquals(113, m.d2());
+
+assertEquals(114, m.d3(1));
+assertEquals(115, m.d3(0));
+
+assertEquals(116, m.d4(1));
+assertEquals(117, m.d4(0));
+
+assertEquals(118, m.d5(1));
+assertEquals(119, m.d5(0));
+
+assertEquals(120, m.d6(0));
+assertEquals(125, m.d6(1));
+assertEquals(122, m.d6(2));
+assertEquals(125, m.d6(3));
+assertEquals(124, m.d6(4));
+assertEquals(125, m.d6(5));