Fix IsDeletable() for HStringAdd, HStringCharCodeAt, HStringCharFromCode.

test/mjsunit/compiler/dead-string-char-from-code.js

Index: test/mjsunit/compiler/dead-string-char-from-code.js
diff --git a/test/mjsunit/compiler/dead-code6.js b/test/mjsunit/compiler/dead-string-char-from-code.js
similarity index 62%
copy from test/mjsunit/compiler/dead-code6.js
copy to test/mjsunit/compiler/dead-string-char-from-code.js
index ec9b8433ddd72187b3f9dab70baf2399fac0cdb2..f9db59d92bbd108ec38e7a1e12cd6342142de208 100644
--- a/test/mjsunit/compiler/dead-code6.js
+++ b/test/mjsunit/compiler/dead-string-char-from-code.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 = %_StringCharFromCode(a);
+    return a; // x is 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 = %_StringCharFromCode(a);
+    var y = %_StringCharFromCode(b);
+    return a; // x and y are both dead
 }
 
 function dead3(a, b) {
-    a == 2 ? (a * b) : (b * a); // dead
-    return a;
+    a = a ? 11 : 12;
+    b = b ? 13 : 14;
+    var x = %_StringCharFromCode(a);
+    var y = %_StringCharFromCode(b);
+    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 test() {
+  assertTrue(dead1(33, 32) == 33);
+  assertTrue(dead2(33, 32) == 33);
+  assertTrue(dead3(33, 32) == 11);
 
-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) == 11);
+
+  assertTrue(dead1(0, 30) == 0);
+  assertTrue(dead2(0, 30) == 0);
+  assertTrue(dead3(0, 32) == 12);
+
+  assertTrue(dead1(true, 0) == true);
+  assertTrue(dead2(true, 0) == true);
+  assertTrue(dead3(true, 0) == 11);
 
-assertTrue(dead3(35, 12) == 35);
-assertTrue(dead3(35, 12) == 35);
+  assertTrue(dead1("true", 0) == "true");
+  assertTrue(dead2("true", 0) == "true");
+  assertTrue(dead3("true", 0) == 11);
+}
+
+test();
+test();
+%OptimizeFunctionOnNextCall(dead1);
+%OptimizeFunctionOnNextCall(dead2);
 %OptimizeFunctionOnNextCall(dead3);
-assertTrue(dead3(35, 12) == 35);
+test();