Fix IsDeletable() for HStringAdd, HStringCharCodeAt, HStringCharFromCode.

test/mjsunit/compiler/dead-string-add-warm.js

Index: test/mjsunit/compiler/dead-string-add-warm.js
diff --git a/test/mjsunit/compiler/dead-code6.js b/test/mjsunit/compiler/dead-string-add-warm.js
similarity index 63%
copy from test/mjsunit/compiler/dead-code6.js
copy to test/mjsunit/compiler/dead-string-add-warm.js
index ec9b8433ddd72187b3f9dab70baf2399fac0cdb2..982f2b9fbdb3a4385d2cd4b2e22028bb1bc43e0b 100644
--- a/test/mjsunit/compiler/dead-code6.js
+++ b/test/mjsunit/compiler/dead-string-add-warm.js
@@ -1,4 +1,4 @@
-// Copyright 2008 the V8 project authors. All rights reserved.
+// Copyright 2013 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:
@@ -26,48 +26,51 @@
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // Flags: --allow-natives-syntax
-// Test some dead code elimination scenarios
 
-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;
+function dead1(a, b) {
+    var x = "a" + "b";
+    return a; // x, "a", and "b" are dead code
 }
 
-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;
+function dead2(a, b) {
+    var x = "0" + a;
+    var y = "0" + b;
+    return a; // x and y are both dead
 }
 
 function dead3(a, b) {
-    a == 2 ? (a * b) : (b * a); // dead
-    return a;
+    a = a ? "1" : "0";
+    b = b ? "1" : "0";
+    var x = a + "0";
+    var y = b + "0";
+    return a; // x and y are both dead
 }
 
-assertTrue(dead1(33, 32) == 33);
-assertTrue(dead1(33, 32) == 33);
-%OptimizeFunctionOnNextCall(dead1);
-assertTrue(dead1(33, 32) == 33);
+function run() {
+  assertTrue(dead1(33, 32) == 33);

[Sven Panne, 2013/07/29 11:48:08]

assertEquals(33, dead1(33, 32);

Likewise below and in other tests.

+  assertTrue(dead2(33, 32) == 33);
+  assertTrue(dead3(33, 32) == "1");
 
-assertTrue(dead2(34, 11) == 34);
-assertTrue(dead2(34, 11) == 34);
-%OptimizeFunctionOnNextCall(dead2);
-assertTrue(dead2(34, 11) == 34);
+  assertTrue(dead1(31, 30) == 31);
+  assertTrue(dead2(31, 30) == 31);
+  assertTrue(dead3(31, 32) == "1");
+
+  assertTrue(dead1(0, 30) == 0);
+  assertTrue(dead2(0, 30) == 0);
+  assertTrue(dead3(0, 32) == "0");
+
+  assertTrue(dead1(true, 0) == true);
+  assertTrue(dead2(true, 0) == true);
+  assertTrue(dead3(true, 0) == "1");
 
-assertTrue(dead3(35, 12) == 35);
-assertTrue(dead3(35, 12) == 35);
+  assertTrue(dead1("true", 0) == "true");
+  assertTrue(dead2("true", 0) == "true");
+  assertTrue(dead3("true", 0) == "1");
+}
+
+run();
+run();
+%OptimizeFunctionOnNextCall(dead1);
+%OptimizeFunctionOnNextCall(dead2);
 %OptimizeFunctionOnNextCall(dead3);
-assertTrue(dead3(35, 12) == 35);
+run();