v8/test/mjsunit/shift-for-integer-div.js

// Copyright 2012 the V8 project authors. All rights reserved.
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//
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// Flags: --allow-natives-syntax --opt --no-always-opt

function divp4(x) {
  return x / 4;
}

%PrepareFunctionForOptimization(divp4);
divp4(8);
divp4(8);
%OptimizeFunctionOnNextCall(divp4);
assertEquals(2, divp4(8));
assertEquals(0.5, divp4(2));


function divn4(x) {
  return x / (-4);
}

%PrepareFunctionForOptimization(divn4);
divn4(8);
divn4(8);
%OptimizeFunctionOnNextCall(divn4);
assertEquals(-2, divn4(8));
// Check for (0 / -x)
assertEquals(-0, divn4(0));


// Check for (kMinInt / -1)
function divn1(x) {
  return x / (-1);
}

%PrepareFunctionForOptimization(divn1);
var two_31 = 1 << 31;
divn1(2);
divn1(2);
%OptimizeFunctionOnNextCall(divn1);
assertEquals(-2, divn1(2));
assertEquals(-two_31, divn1(two_31));


//Check for truncating to int32 case
function divp4t(x) {
  return (x / 4) | 0;
}

%PrepareFunctionForOptimization(divp4t);
divp4t(8);
divp4t(8);
%OptimizeFunctionOnNextCall(divp4t);
assertEquals(-1, divp4t(-5));
assertEquals(1, divp4t(5));
assertOptimized(divp4t);

function divn4t(x) {
  return (x / -4) | 0;
}

%PrepareFunctionForOptimization(divn4t);
divn4t(8);
divn4t(8);
%OptimizeFunctionOnNextCall(divn4t);
assertEquals(1, divn4t(-5));
assertEquals(-1, divn4t(5));
assertOptimized(divn4t);

// Check kMinInt case.
function div_by_two(x) {
  return (x / 2) | 0;
}

%PrepareFunctionForOptimization(div_by_two);
div_by_two(12);
div_by_two(34);
%OptimizeFunctionOnNextCall(div_by_two);
div_by_two(56);
assertEquals(-(1 << 30), div_by_two(1 << 31));