v8/test/mjsunit/math-floor-of-div.js

// Copyright 2012 the V8 project authors. All rights reserved.
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// modification, are permitted provided that the following conditions are
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//
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// Flags: --allow-natives-syntax --enable-sudiv

// Use this function as reference. Make sure it is not inlined.
function div(a, b) {
  return a / b;
}

var limit = 0x1000000;
var exhaustive_limit = 100;
var step = 10;
var values = [
  0x10000001, 0x12345678,
  -0x789abcdf,  // 0x87654321
  0x01234567, 0x76543210,
  -0x80000000,  // 0x80000000
  0x7fffffff,
  -0x0fffffff,  // 0xf0000001
  0x00000010,
  -0x01000000  // 0xff000000
];

function test_div() {
  var c = 0;
  for (var k = 0; k <= limit; k++) {
    if (k > exhaustive_limit) {
      c += step;
      k += c;
    }
    assertEquals(Math.floor(div(k, 1)), Math.floor(k / 1));
    assertEquals(Math.floor(div(k, -1)), Math.floor(k / -1));
    assertEquals(Math.floor(div(k, 2)), Math.floor(k / 2));
    assertEquals(Math.floor(div(k, -2)), Math.floor(k / -2));
    assertEquals(Math.floor(div(k, 3)), Math.floor(k / 3));
    assertEquals(Math.floor(div(k, -3)), Math.floor(k / -3));
    assertEquals(Math.floor(div(k, 4)), Math.floor(k / 4));
    assertEquals(Math.floor(div(k, -4)), Math.floor(k / -4));
    assertEquals(Math.floor(div(k, 5)), Math.floor(k / 5));
    assertEquals(Math.floor(div(k, -5)), Math.floor(k / -5));
    assertEquals(Math.floor(div(k, 6)), Math.floor(k / 6));
    assertEquals(Math.floor(div(k, -6)), Math.floor(k / -6));
    assertEquals(Math.floor(div(k, 7)), Math.floor(k / 7));
    assertEquals(Math.floor(div(k, -7)), Math.floor(k / -7));
    assertEquals(Math.floor(div(k, 8)), Math.floor(k / 8));
    assertEquals(Math.floor(div(k, -8)), Math.floor(k / -8));
    assertEquals(Math.floor(div(k, 9)), Math.floor(k / 9));
    assertEquals(Math.floor(div(k, -9)), Math.floor(k / -9));
    assertEquals(Math.floor(div(k, 10)), Math.floor(k / 10));
    assertEquals(Math.floor(div(k, -10)), Math.floor(k / -10));
    assertEquals(Math.floor(div(k, 11)), Math.floor(k / 11));
    assertEquals(Math.floor(div(k, -11)), Math.floor(k / -11));
    assertEquals(Math.floor(div(k, 12)), Math.floor(k / 12));
    assertEquals(Math.floor(div(k, -12)), Math.floor(k / -12));
    assertEquals(Math.floor(div(k, 13)), Math.floor(k / 13));
    assertEquals(Math.floor(div(k, -13)), Math.floor(k / -13));
    assertEquals(Math.floor(div(k, 14)), Math.floor(k / 14));
    assertEquals(Math.floor(div(k, -14)), Math.floor(k / -14));
    assertEquals(Math.floor(div(k, 15)), Math.floor(k / 15));
    assertEquals(Math.floor(div(k, -15)), Math.floor(k / -15));
    assertEquals(Math.floor(div(k, 16)), Math.floor(k / 16));
    assertEquals(Math.floor(div(k, -16)), Math.floor(k / -16));
    assertEquals(Math.floor(div(k, 17)), Math.floor(k / 17));
    assertEquals(Math.floor(div(k, -17)), Math.floor(k / -17));
    assertEquals(Math.floor(div(k, 18)), Math.floor(k / 18));
    assertEquals(Math.floor(div(k, -18)), Math.floor(k / -18));
    assertEquals(Math.floor(div(k, 19)), Math.floor(k / 19));
    assertEquals(Math.floor(div(k, -19)), Math.floor(k / -19));
    assertEquals(Math.floor(div(k, 20)), Math.floor(k / 20));
    assertEquals(Math.floor(div(k, -20)), Math.floor(k / -20));
    assertEquals(Math.floor(div(k, 21)), Math.floor(k / 21));
    assertEquals(Math.floor(div(k, -21)), Math.floor(k / -21));
    assertEquals(Math.floor(div(k, 22)), Math.floor(k / 22));
    assertEquals(Math.floor(div(k, -22)), Math.floor(k / -22));
    assertEquals(Math.floor(div(k, 23)), Math.floor(k / 23));
    assertEquals(Math.floor(div(k, -23)), Math.floor(k / -23));
    assertEquals(Math.floor(div(k, 24)), Math.floor(k / 24));
    assertEquals(Math.floor(div(k, -24)), Math.floor(k / -24));
    assertEquals(Math.floor(div(k, 25)), Math.floor(k / 25));
    assertEquals(Math.floor(div(k, -25)), Math.floor(k / -25));
    assertEquals(Math.floor(div(k, 125)), Math.floor(k / 125));
    assertEquals(Math.floor(div(k, -125)), Math.floor(k / -125));
    assertEquals(Math.floor(div(k, 625)), Math.floor(k / 625));
    assertEquals(Math.floor(div(k, -625)), Math.floor(k / -625));
  }
  c = 0;
  for (var k = 0; k <= limit; k++) {
    if (k > exhaustive_limit) {
      c += step;
      k += c;
    }
    assertEquals(Math.floor(div(-k, 1)), Math.floor(-k / 1));
    assertEquals(Math.floor(div(-k, -1)), Math.floor(-k / -1));
    assertEquals(Math.floor(div(-k, 2)), Math.floor(-k / 2));
    assertEquals(Math.floor(div(-k, -2)), Math.floor(-k / -2));
    assertEquals(Math.floor(div(-k, 3)), Math.floor(-k / 3));
    assertEquals(Math.floor(div(-k, -3)), Math.floor(-k / -3));
    assertEquals(Math.floor(div(-k, 4)), Math.floor(-k / 4));
    assertEquals(Math.floor(div(-k, -4)), Math.floor(-k / -4));
    assertEquals(Math.floor(div(-k, 5)), Math.floor(-k / 5));
    assertEquals(Math.floor(div(-k, -5)), Math.floor(-k / -5));
    assertEquals(Math.floor(div(-k, 6)), Math.floor(-k / 6));
    assertEquals(Math.floor(div(-k, -6)), Math.floor(-k / -6));
    assertEquals(Math.floor(div(-k, 7)), Math.floor(-k / 7));
    assertEquals(Math.floor(div(-k, -7)), Math.floor(-k / -7));
    assertEquals(Math.floor(div(-k, 8)), Math.floor(-k / 8));
    assertEquals(Math.floor(div(-k, -8)), Math.floor(-k / -8));
    assertEquals(Math.floor(div(-k, 9)), Math.floor(-k / 9));
    assertEquals(Math.floor(div(-k, -9)), Math.floor(-k / -9));
    assertEquals(Math.floor(div(-k, 10)), Math.floor(-k / 10));
    assertEquals(Math.floor(div(-k, -10)), Math.floor(-k / -10));
    assertEquals(Math.floor(div(-k, 11)), Math.floor(-k / 11));
    assertEquals(Math.floor(div(-k, -11)), Math.floor(-k / -11));
    assertEquals(Math.floor(div(-k, 12)), Math.floor(-k / 12));
    assertEquals(Math.floor(div(-k, -12)), Math.floor(-k / -12));
    assertEquals(Math.floor(div(-k, 13)), Math.floor(-k / 13));
    assertEquals(Math.floor(div(-k, -13)), Math.floor(-k / -13));
    assertEquals(Math.floor(div(-k, 14)), Math.floor(-k / 14));
    assertEquals(Math.floor(div(-k, -14)), Math.floor(-k / -14));
    assertEquals(Math.floor(div(-k, 15)), Math.floor(-k / 15));
    assertEquals(Math.floor(div(-k, -15)), Math.floor(-k / -15));
    assertEquals(Math.floor(div(-k, 16)), Math.floor(-k / 16));
    assertEquals(Math.floor(div(-k, -16)), Math.floor(-k / -16));
    assertEquals(Math.floor(div(-k, 17)), Math.floor(-k / 17));
    assertEquals(Math.floor(div(-k, -17)), Math.floor(-k / -17));
    assertEquals(Math.floor(div(-k, 18)), Math.floor(-k / 18));
    assertEquals(Math.floor(div(-k, -18)), Math.floor(-k / -18));
    assertEquals(Math.floor(div(-k, 19)), Math.floor(-k / 19));
    assertEquals(Math.floor(div(-k, -19)), Math.floor(-k / -19));
    assertEquals(Math.floor(div(-k, 20)), Math.floor(-k / 20));
    assertEquals(Math.floor(div(-k, -20)), Math.floor(-k / -20));
    assertEquals(Math.floor(div(-k, 21)), Math.floor(-k / 21));
    assertEquals(Math.floor(div(-k, -21)), Math.floor(-k / -21));
    assertEquals(Math.floor(div(-k, 22)), Math.floor(-k / 22));
    assertEquals(Math.floor(div(-k, -22)), Math.floor(-k / -22));
    assertEquals(Math.floor(div(-k, 23)), Math.floor(-k / 23));
    assertEquals(Math.floor(div(-k, -23)), Math.floor(-k / -23));
    assertEquals(Math.floor(div(-k, 24)), Math.floor(-k / 24));
    assertEquals(Math.floor(div(-k, -24)), Math.floor(-k / -24));
    assertEquals(Math.floor(div(-k, 25)), Math.floor(-k / 25));
    assertEquals(Math.floor(div(-k, -25)), Math.floor(-k / -25));
    assertEquals(Math.floor(div(-k, 125)), Math.floor(-k / 125));
    assertEquals(Math.floor(div(-k, -125)), Math.floor(-k / -125));
    assertEquals(Math.floor(div(-k, 625)), Math.floor(-k / 625));
    assertEquals(Math.floor(div(-k, -625)), Math.floor(-k / -625));
  }
  // Test for edge cases.
  // Use (values[key] | 0) to force the integer type.
  for (var i = 0; i < values.length; i++) {
    for (var j = 0; j < values.length; j++) {
      assertEquals(
          Math.floor(div(values[i] | 0, values[j] | 0)),
          Math.floor((values[i] | 0) / (values[j] | 0)));
      assertEquals(
          Math.floor(div(-(values[i] | 0), values[j] | 0)),
          Math.floor(-(values[i] | 0) / (values[j] | 0)));
      assertEquals(
          Math.floor(div(values[i] | 0, -(values[j] | 0))),
          Math.floor((values[i] | 0) / -(values[j] | 0)));
      assertEquals(
          Math.floor(div(-(values[i] | 0), -(values[j] | 0))),
          Math.floor(-(values[i] | 0) / -(values[j] | 0)));
    }
  }
};
%PrepareFunctionForOptimization(test_div);
test_div();
%OptimizeFunctionOnNextCall(test_div);
test_div();

// Test for flooring correctness.
var values2 = [1, 3, 10, 99, 100, 101, 0x7fffffff];
function test_div2() {
  for (var i = 0; i < values2.length; i++) {
    for (var j = 0; j < values2.length; j++) {
      assertEquals(
          Math.floor(div(values2[i] | 0, values2[j] | 0)),
          Math.floor((values2[i] | 0) / (values2[j] | 0)));
      assertEquals(
          Math.floor(div(-(values2[i] | 0), values2[j] | 0)),
          Math.floor(-(values2[i] | 0) / (values2[j] | 0)));
      assertEquals(
          Math.floor(div(values2[i] | 0, -(values2[j] | 0))),
          Math.floor((values2[i] | 0) / -(values2[j] | 0)));
      assertEquals(
          Math.floor(div(-(values2[i] | 0), -(values2[j] | 0))),
          Math.floor(-(values2[i] | 0) / -(values2[j] | 0)));
    }
  }
};
%PrepareFunctionForOptimization(test_div2);
test_div2();
%OptimizeFunctionOnNextCall(test_div2);
test_div2();


// Test for negative zero, overflow and division by 0.
// Separate the tests to prevent deoptimizations from making the other optimized
// test unreachable.

// We box the value in an array to avoid constant propagation.
var neg_one_in_array = [-1];
var zero_in_array = [0];
var min_int_in_array = [-2147483648];

// Test for dividing by constant.
function IsNegativeZero(x) {
  assertTrue(x == 0);  // Is 0 or -0.
  var y = 1 / x;
  assertFalse(isFinite(y));
  return y < 0;
}

function test_div_deopt_minus_zero() {
  for (var i = 0; i < 2; ++i) {
    assertTrue(IsNegativeZero(Math.floor((zero_in_array[0] | 0) / -1)));
  }
};
%PrepareFunctionForOptimization(test_div_deopt_minus_zero);
function test_div_deopt_overflow() {
  for (var i = 0; i < 2; ++i) {
    // We use '| 0' to force the representation to int32.
    assertEquals(
        -min_int_in_array[0], Math.floor((min_int_in_array[0] | 0) / -1));
  }
};
%PrepareFunctionForOptimization(test_div_deopt_overflow);
function test_div_deopt_div_by_zero() {
  for (var i = 0; i < 2; ++i) {
    assertEquals(div(i, 0), Math.floor(i / 0));
  }
};
%PrepareFunctionForOptimization(test_div_deopt_div_by_zero);
test_div_deopt_minus_zero();
test_div_deopt_overflow();
test_div_deopt_div_by_zero();
%OptimizeFunctionOnNextCall(test_div_deopt_minus_zero);
%OptimizeFunctionOnNextCall(test_div_deopt_overflow);
%OptimizeFunctionOnNextCall(test_div_deopt_div_by_zero);
test_div_deopt_minus_zero();
test_div_deopt_overflow();
test_div_deopt_div_by_zero();

// Test for dividing by variable.
function test_div_deopt_minus_zero_v() {
  for (var i = 0; i < 2; ++i) {
    assertTrue(IsNegativeZero(
        Math.floor((zero_in_array[0] | 0) / neg_one_in_array[0])));
  }
};
%PrepareFunctionForOptimization(test_div_deopt_minus_zero_v);
function test_div_deopt_overflow_v() {
  for (var i = 0; i < 2; ++i) {
    // We use '| 0' to force the representation to int32.
    assertEquals(
        -min_int_in_array[0],
        Math.floor((min_int_in_array[0] | 0) / neg_one_in_array[0]));
  }
};
%PrepareFunctionForOptimization(test_div_deopt_overflow_v);
function test_div_deopt_div_by_zero_v() {
  for (var i = 0; i < 2; ++i) {
    assertEquals(div(i, 0), Math.floor(i / zero_in_array[0]));
  }
};
%PrepareFunctionForOptimization(test_div_deopt_div_by_zero_v);
test_div_deopt_minus_zero_v();
test_div_deopt_overflow_v();
test_div_deopt_div_by_zero_v();
%OptimizeFunctionOnNextCall(test_div_deopt_minus_zero_v);
%OptimizeFunctionOnNextCall(test_div_deopt_overflow_v);
%OptimizeFunctionOnNextCall(test_div_deopt_div_by_zero_v);
test_div_deopt_minus_zero_v();
test_div_deopt_overflow_v();
test_div_deopt_div_by_zero_v();


// Test for flooring division with negative dividend.
function flooring_div_by_3(y) {
  return Math.floor(y / 3);
};
%PrepareFunctionForOptimization(flooring_div_by_3);
assertEquals(-1, flooring_div_by_3(-2));
assertEquals(-1, flooring_div_by_3(-2));
%OptimizeFunctionOnNextCall(flooring_div_by_3);
assertEquals(-1, flooring_div_by_3(-2));