v8/test/mjsunit/compiler/number-divide.js

// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Flags: --allow-natives-syntax --opt --noalways-opt

// Test that NumberDivide with Number feedback works if only in the
// end SimplifiedLowering figures out that the inputs to this operation
// are actually Unsigned32.
(function() {
  // We need a separately polluted % with NumberOrOddball feedback.
  function bar(x) { return x / 2; }
  bar(undefined);  // The % feedback is now NumberOrOddball.

  // Now just use the gadget above in a way that only after RETYPE
  // in SimplifiedLowering we find out that the `x` is actually in
  // Unsigned32 range (based on taking the SignedSmall feedback on
  // the + operator).
  function foo(x) {
    x = (x >>> 0) + 1;
    return bar(x) | 0;
  }

  %PrepareFunctionForOptimization(foo);
  assertEquals(1, foo(1));
  assertEquals(1, foo(2));
  assertEquals(2, foo(3));
  assertEquals(2, foo(4));
  %OptimizeFunctionOnNextCall(foo);
  assertEquals(1, foo(1));
  assertEquals(1, foo(2));
  assertEquals(2, foo(3));
  assertEquals(2, foo(4));
  assertOptimized(foo);
})();

// Test that NumberDivide with Number feedback works if only in the
// end SimplifiedLowering figures out that the inputs to this operation
// are actually Signed32.
(function() {
  // We need a separately polluted % with NumberOrOddball feedback.
  function bar(x) { return x / 2; }
  bar(undefined);  // The % feedback is now NumberOrOddball.

  // Now just use the gadget above in a way that only after RETYPE
  // in SimplifiedLowering we find out that the `x` is actually in
  // Signed32 range (based on taking the SignedSmall feedback on
  // the + operator).
  function foo(x) {
    x = (x | 0) + 1;
    return bar(x) | 0;
  }

  %PrepareFunctionForOptimization(foo);
  assertEquals(1, foo(1));
  assertEquals(1, foo(2));
  assertEquals(2, foo(3));
  assertEquals(2, foo(4));
  %OptimizeFunctionOnNextCall(foo);
  assertEquals(1, foo(1));
  assertEquals(1, foo(2));
  assertEquals(2, foo(3));
  assertEquals(2, foo(4));
  assertOptimized(foo);
})();

// Test that SpeculativeNumberDivide turns into CheckedInt32Div, and
// that the "known power of two divisor" optimization works correctly.
(function() {
  function foo(x) { return (x | 0) / 2; }

  // Warmup with proper int32 divisions.
  %PrepareFunctionForOptimization(foo);
  assertEquals(1, foo(2));
  assertEquals(2, foo(4));
  %OptimizeFunctionOnNextCall(foo);
  assertEquals(3, foo(6));
  assertOptimized(foo);

  // Make optimized code fail.
  assertEquals(0.5, foo(1));
  assertUnoptimized(foo);

  // Try again with the new feedback, and now it should stay optimized.
  %PrepareFunctionForOptimization(foo);
  %OptimizeFunctionOnNextCall(foo);
  assertEquals(4, foo(8));
  assertOptimized(foo);
  assertEquals(0.5, foo(1));
  assertOptimized(foo);
})();

// Test that SpeculativeNumberDivide turns into CheckedInt32Div, and
// that the optimized code properly bails out on "division by zero".
(function() {
  function foo(x, y) { return x / y; }

  // Warmup with proper int32 divisions.
  %PrepareFunctionForOptimization(foo);
  assertEquals(2, foo(4, 2));
  assertEquals(2, foo(8, 4));
  %OptimizeFunctionOnNextCall(foo);
  assertEquals(1, foo(2, 2));
  assertOptimized(foo);

  // Make optimized code fail.
  assertEquals(Infinity, foo(1, 0));
  assertUnoptimized(foo);

  // Try again with the new feedback, and now it should stay optimized.
  %PrepareFunctionForOptimization(foo);
  %OptimizeFunctionOnNextCall(foo);
  assertEquals(2, foo(2, 1));
  assertOptimized(foo);
  assertEquals(Infinity, foo(1, 0));
  assertOptimized(foo);
})();

// Test that SpeculativeNumberDivide turns into CheckedInt32Div, and
// that the optimized code properly bails out on minus zero.
(function() {
  function foo(x, y) { return x / y; }

  // Warmup with proper int32 divisions.
  %PrepareFunctionForOptimization(foo);
  assertEquals(2, foo(4, 2));
  assertEquals(2, foo(8, 4));
  %OptimizeFunctionOnNextCall(foo);
  assertEquals(1, foo(2, 2));
  assertOptimized(foo);

  // Make optimized code fail.
  assertEquals(-0, foo(0, -1));
  assertUnoptimized(foo);

  // Try again with the new feedback, and now it should stay optimized.
  %PrepareFunctionForOptimization(foo);
  %OptimizeFunctionOnNextCall(foo);
  assertEquals(2, foo(2, 1));
  assertOptimized(foo);
  assertEquals(-0, foo(0, -1));
  assertOptimized(foo);
})();

// Test that SpeculativeNumberDivide turns into CheckedInt32Div, and
// that the optimized code properly bails out if result is -kMinInt.
(function() {
  function foo(x, y) { return x / y; }

  // Warmup with proper int32 divisions.
  %PrepareFunctionForOptimization(foo);
  assertEquals(2, foo(4, 2));
  assertEquals(2, foo(8, 4));
  %OptimizeFunctionOnNextCall(foo);
  assertEquals(1, foo(2, 2));
  assertOptimized(foo);

  // Make optimized code fail.
  assertEquals(2147483648, foo(-2147483648, -1));
  assertUnoptimized(foo);

  // Try again with the new feedback, and now it should stay optimized.
  %PrepareFunctionForOptimization(foo);
  %OptimizeFunctionOnNextCall(foo);
  assertEquals(2, foo(2, 1));
  assertOptimized(foo);
  assertEquals(2147483648, foo(-2147483648, -1));
  assertOptimized(foo);
})();

// Test that SpeculativeNumberDivide turns into CheckedUint32Div, and
// that the "known power of two divisor" optimization works correctly.
(function() {
  function foo(s) { return s.length / 2; }

  // Warmup with proper uint32 divisions.
  %PrepareFunctionForOptimization(foo);
  assertEquals(1, foo("ab".repeat(1)));
  assertEquals(2, foo("ab".repeat(2)));
  %OptimizeFunctionOnNextCall(foo);
  assertEquals(3, foo("ab".repeat(3)));
  assertOptimized(foo);

  // Make optimized code fail.
  assertEquals(0.5, foo("a"));
  assertUnoptimized(foo);

  // Try again with the new feedback, and now it should stay optimized.
  %PrepareFunctionForOptimization(foo);
  %OptimizeFunctionOnNextCall(foo);
  assertEquals(4, foo("ab".repeat(4)));
  assertOptimized(foo);
  assertEquals(0.5, foo("a"));
  assertOptimized(foo);
})();

// Test that SpeculativeNumberDivide turns into CheckedUint32Div, and
// that the optimized code properly bails out on "division by zero".
(function() {
  function foo(x, y) { return (x >>> 0) / (y >>> 0); }

  // Warmup with proper uint32 divisions.
  %PrepareFunctionForOptimization(foo);
  assertEquals(2, foo(4, 2));
  assertEquals(2, foo(8, 4));
  %OptimizeFunctionOnNextCall(foo);
  assertEquals(1, foo(2, 2));
  assertOptimized(foo);

  // Make optimized code fail.
  assertEquals(Infinity, foo(1, 0));
  assertUnoptimized(foo);

  // Try again with the new feedback, and now it should stay optimized.
  %PrepareFunctionForOptimization(foo);
  %OptimizeFunctionOnNextCall(foo);
  assertEquals(2, foo(2, 1));
  assertOptimized(foo);
  assertEquals(Infinity, foo(1, 0));
  assertOptimized(foo);
})();