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[RISC-V] Test TotalOrderIeee754ComparerTests: Fix NFloat - NaN testcases for RISC-V #97340

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merged 5 commits into from
Feb 1, 2024
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[RISC-V] Test TotalOrderIeee754ComparerTests: Fix NFloat - NaN testcases for RISC-V #97340

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18cd0cd
Fix ieeeComparerTests NFloat NaN testcases for RISC-V
Jan 22, 2024
0992c57
Fix comment
Jan 22, 2024
ee575ae
Specify test data for NaN test cases based on platform bitness
Jan 29, 2024
fec33c4
Delete extra comment
Jan 30, 2024
1f804db
Fix CI failure
Jan 31, 2024
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32 changes: 31 additions & 1 deletion ...stem.Runtime/tests/System.Runtime.Tests/System/Numerics/TotalOrderIeee754ComparerTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -94,8 +94,38 @@ public void TotalOrderTestHalf(Half x, Half y, int result)
Assert.Equal(result, Math.Sign(comparer.Compare(x, y)));
}

public static IEnumerable<object[]> NFloatTestData
{
get
{
yield return new object[] { 0.0f, 0.0f, 0 };
yield return new object[] { -0.0f, -0.0f, 0 };
yield return new object[] { 0.0f, -0.0f, 1 };
yield return new object[] { -0.0f, 0.0f, -1 };
yield return new object[] { 0.0f, 1.0f, -1 };
yield return new object[] { float.PositiveInfinity, 1.0f, 1 };
yield return new object[] { BitConverter.UInt32BitsToSingle(0x7FC00000), 1.0f, 1 };
yield return new object[] { BitConverter.UInt32BitsToSingle(0x7FC00000), float.PositiveInfinity, 1 };
yield return new object[] { float.NaN, float.NaN, 0 };
if (PlatformDetection.IsRiscV64Process) // float->double cast does not preserve NaN payload and sign on RISC-V
{
yield return new object[] { BitConverter.UInt32BitsToSingle(0xFFC00000), float.NegativeInfinity, 1 };
yield return new object[] { BitConverter.UInt32BitsToSingle(0xFFC00000), -1.0f, 1 };
yield return new object[] { BitConverter.UInt32BitsToSingle(0xFFC00000), BitConverter.UInt32BitsToSingle(0x7FC00000), 0 };
yield return new object[] { BitConverter.UInt32BitsToSingle(0x7FC00000), BitConverter.UInt32BitsToSingle(0x7FC00001), 0 }; // implementation defined, not part of IEEE 754 totalOrder
}
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I'm not sure this is the desirable/best fix.

The overall preservation of a NaN sign/payload is implementation defined; however, in the face of a NaN with sign and/or payload, IEEE 754 totalOrder describes exact handling/behavior that is required to be followed.

The test was using SingleTestData for simplicity purposes; however in the face of RiscV it is likely better to fix the test to take NFloat and to enumerate bitwise correct values depending on the underlying bitness of the platform. That way encountered NaN with sign/payload (such as from the developer doing a bitcast where RiscV doesn't normalize) can be validated.

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Do you mean to enumerate bitwise correct values only for NaN values or for all test values?

else
{
yield return new object[] { BitConverter.UInt32BitsToSingle(0xFFC00000), float.NegativeInfinity, -1 };
yield return new object[] { BitConverter.UInt32BitsToSingle(0xFFC00000), -1.0f, -1 };
yield return new object[] { BitConverter.UInt32BitsToSingle(0xFFC00000), BitConverter.UInt32BitsToSingle(0x7FC00000), -1 };
yield return new object[] { BitConverter.UInt32BitsToSingle(0x7FC00000), BitConverter.UInt32BitsToSingle(0x7FC00001), -1 }; // implementation defined, not part of IEEE 754 totalOrder
}
}
}

[Theory]
[MemberData(nameof(SingleTestData))]
[MemberData(nameof(NFloatTestData))]
public void TotalOrderTestNFloat(float x, float y, int result)
{
var comparer = new TotalOrderIeee754Comparer<NFloat>();
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