v8/test/mjsunit/compiler/dead-string-char-from-code.js

// Copyright 2013 the V8 project authors. All rights reserved.
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// modification, are permitted provided that the following conditions are
// met:
//
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// Flags: --allow-natives-syntax

function dead1(a, b) {
    var x = %_StringCharFromCode(a);
    return a; // x is dead code
}

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 = a ? 11 : 12;
    b = b ? 13 : 14;
    var x = %_StringCharFromCode(a);
    var y = %_StringCharFromCode(b);
    return a; // x and y are both dead
}

function test() {
    assertEquals(33, dead1(33, 32));
    assertEquals(33, dead2(33, 32));
    assertEquals(11, dead3(33, 32));

    assertEquals(31, dead1(31, 30));
    assertEquals(31, dead2(31, 30));
    assertEquals(11, dead3(31, 32));

    assertEquals(0, dead1(0, 30));
    assertEquals(0, dead2(0, 30));
    assertEquals(12, dead3(0, 32));

    assertEquals(true, dead1(true, 0));
    assertEquals(true, dead2(true, 0));
    assertEquals(11, dead3(true, 0));

    assertEquals("true", dead1("true", 0));
    assertEquals("true", dead2("true", 0));
    assertEquals(11, dead3("true", 0));
}

test();
test();
%OptimizeFunctionOnNextCall(dead1);
%OptimizeFunctionOnNextCall(dead2);
%OptimizeFunctionOnNextCall(dead3);
test();