Improve dead code elimination by transitively marking live code and removing all dead code. Replace…

test/mjsunit/compiler/dead-code6.js

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
 //       with the distribution.
 //     * Neither the name of Google Inc. nor the names of its
 //       contributors may be used to endorse or promote products derived
 //       from this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // Flags: --allow-natives-syntax
+// Test some dead code elimination scenarios
 
-obj = new Uint8ClampedArray(10);
-
-// Test that undefined gets properly clamped in Crankshafted pixel array
-// assignments.
-function set_pixel(obj, arg) {
-  obj[0] = arg;
+function dead1(x, y) {
+    var a = x | 0, b = y | 0;
+    a * b;
+    a << b;
+    a >> b;
+    a >>> b;
+    a | b;
+    a & b;
+    a ^ b;
+    return x;
 }
 
-set_pixel(obj, 1.5);
-set_pixel(obj, NaN);
-%OptimizeFunctionOnNextCall(set_pixel);
-set_pixel(obj, undefined);
-set_pixel(obj, undefined);
+function dead2(x, y) {
+    var a = x | 0, b = y | 0;
+    (a | 0) * b;
+    (a | 0) << b;
+    (a | 0) >> b;
+    (a | 0) >>> b;
+    (a | 0) | b;
+    (a | 0) & b;
+    (a | 0) ^ b;
+    return x;
+}
 
-assertEquals(0, obj[0]);
+function dead3(a, b) {
+    a == 2 ? (a * b) : (b * a); // dead
+    return a;
+}
+
+assertTrue(dead1(33, 32) == 33);
+assertTrue(dead1(33, 32) == 33);
+%OptimizeFunctionOnNextCall(dead1);
+assertTrue(dead1(33, 32) == 33);
+
+assertTrue(dead2(34, 11) == 34);
+assertTrue(dead2(34, 11) == 34);
+%OptimizeFunctionOnNextCall(dead2);
+assertTrue(dead2(34, 11) == 34);
+
+assertTrue(dead3(35, 12) == 35);
+assertTrue(dead3(35, 12) == 35);
+%OptimizeFunctionOnNextCall(dead3);
+assertTrue(dead3(35, 12) == 35);