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System.Runtime.Intrinsics.Vector128.Create() bug inside of for loop #43569
Description
Description
I believe that I have found a regression with the way Vector128 structs are created using Vector128.Create(float, float, float, float) when converting from doubles. For example, the following code console writes <1, 2, 3, 4> as expected:
double[] array = new[] { 1.0, 2, 3, 4 };
Vector128<float> x = Vector128.Create(Convert.ToSingle(array[0]), Convert.ToSingle(array[1]), Convert.ToSingle(array[2]), Convert.ToSingle(array[3]));
Console.WriteLine(x);However, simply putting the code inside a for loop (or while for that matter) causes a console write of <1, 2, 3, 2>:
double[] array = new[] { 1.0, 2, 3, 4 };
Vector128<float> x = Vector128<float>.Zero;
for (int i = 0; i < 1; i++)
x = Vector128.Create(Convert.ToSingle(array[0]), Convert.ToSingle(array[1]), Convert.ToSingle(array[2]), Convert.ToSingle(array[3]));
Console.WriteLine(x);Configuration
dotnet 5.0.100-rc.2.20479.15
Windows 10 Enterprise 2004 (19041.572)
x64 in Release mode ... in Debug mode, things work as expected.
Regression
Yes, this is a regression. I tried this using .NET Core 3.1 (3.1.402) and got the expected output either way.
Other information
One way to work around this issue is to set the 3rd element again manually using WithElement() like so:
x = x.WithElement(3, Convert.ToSingle(array[3]));Hope this is helpful, please let me know if you have any questions.
Thanks!
Activity
EgorBo commentedon Oct 19, 2020
Minimal repro:
Missing
GTF_CALLflag?fgUpdateInlineReturnExpressionPlaceHolderjust skips the tree and doesn't walk it to findGT_RET_EXPRit has to replace./cc @dotnet/jit-contrib
AndyAyersMS commentedon Nov 20, 2020
Reopening to port fix to 5.0.
AndyAyersMS commentedon Nov 23, 2020
Fix is merged into 5.0 and should appear in 5.0.1.