ARM64 Vector2 multiplication breaks in .NET 8 #98137
Description
Description
On Linux and MacOS, various Vector2 floating point multiplications break after running for a few hundred milliseconds.
Running this code in Release Mode on a dotnet new console application on ARM64 results in the Y component of the vector being zero.
using System.Numerics;
while (true)
{
Thread.Sleep(10);
Step(4.0f);
}
static void Step(float number)
{
var variable = Vector2.One * number;
if (variable.X != variable.Y)
throw new Exception("Components don't match");
Console.WriteLine(variable);
}This does not occur in Debug Mode. If I don't wrap the code in a function (Step) it doesn't seem to happen. If I hard code the floating value (Vector2.One * 4.0f) it doesn't seem to happen.
Reproduction Steps
Simply create a new console project in .NET 8 and run the above code in Program.cs with dotnet run -c Release. After running for a few hundred milliseconds the application will throw an exception.
Expected behavior
Multiplication should always result in <4,4>
Actual behavior
Multiplication results in <4,0> after several hundred milliseconds
Regression?
Does not occur in .NET 7, only .NET 8
Known Workarounds
No response
Configuration
.NET 8, ARM64, MacOS (have had reports of this same problem on ARM64 Linux)
Other information
This has been an issue found in our open source game Celeste 64 for users running the game on ARM64 for both MacOS and Linux. I personally have only tested on MacOS.