[android 32bit build] issues with mathematical calculation

[AdamChlupacek]

Hello,

I have recently upgraded my RN application from RN 54.4 to 61.1. The application now works great in the 64 bit version, but on 32 bit version I am having issues with mathematical calculations at random times.

React Native version: 61.1 System: OS: macOS Mojave 10.14.5 CPU: (12) x64 Intel(R) Core(TM) i9-8950HK CPU @ 2.90GHz Memory: 1.99 GB / 32.00 GB Shell: 5.3 - /bin/zsh Binaries: Node: 12.10.0 - /usr/local/bin/node npm: 6.11.3 - /usr/local/bin/npm Watchman: 4.9.0 - /usr/local/bin/watchman SDKs: iOS SDK: Platforms: iOS 12.2, macOS 10.14, tvOS 12.2, watchOS 5.2 Android SDK: API Levels: 23, 25, 26, 28 Build Tools: 23.0.1, 25.0.0, 25.0.1, 25.0.2, 26.0.1, 26.0.2, 26.0.3, 27.0.3, 28.0.2, 28.0.3 System Images: android-23 | Google APIs ARM EABI v7a, android-23 | Google APIs Intel x86 Atom_64, android-28 | Google Play Intel x86 Atom IDEs: Android Studio: 3.5 AI-191.8026.42.35.5791312 Xcode: 10.2/10E125 - /usr/bin/xcodebuild npmPackages: react: 16.9.0 => 16.9.0 react-native: 0.61.1 => 0.61.1 npmGlobalPackages: react-native-cli: 2.0.1 react-native: 0.61.1

Steps To Reproduce

Run following code on 32bit platform

for (var idx = 0; idx < 10000; idx++) {

    var hash = 2026056511
    var level = 0
    var bitmap = -128083075

    var index = (31 & ((hash >>> level) | 0));
    var mask = (1 << index);

    var i = (bitmap & (((-1) + mask) | 0));
    var t1 = ((i - ((i >> 1) & 1431655765)) | 0);
    var t2 = (((t1 & 858993459) + ((t1 >> 2) & 858993459)) | 0);
    var offset = ($imul(16843009, (252645135 & ((t2 + (t2 >> 4)) | 0))) >> 24)

    console.info("XXXXXO wrong offset", offset);
}

You will see that the print will output either 20 or 21, and the values change as the loop is performing. I have inseted this sniped just before the end of the index.js

Describe what you expected to happen:

I would expect that the calculation would output the same results for the same inputs.

[AdamChlupacek]

Forgot to add the $imul implementation

var $imul = Math.imul || (function(a, b) {
  // See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/imul
  var ah = (a >>> 16) & 0xffff;
  var al = a & 0xffff;
  var bh = (b >>> 16) & 0xffff;
  var bl = b & 0xffff;
  // the shift by 0 fixes the sign on the high part
  // the final |0 converts the unsigned value into a signed value
  return ((al * bl) + (((ah * bl + al * bh) << 16) >>> 0) | 0);
});

[stale[bot]]

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[stale[bot]]

Closing this issue after a prolonged period of inactivity. If this issue is still present in the latest release, please feel free to create a new issue with up-to-date information.