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Add fast-path optimizations for Char.IsDigit in performance-critical paths #12030

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Merged
merged 7 commits into from
Jun 23, 2025
Merged

Add fast-path optimizations for Char.IsDigit in performance-critical paths #12030

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7863e84
Initial plan for issue
Copilot Jun 17, 2025
806731d
Add fast-path optimizations for Char.IsDigit in performance-critical …
Copilot Jun 17, 2025
721ed1a
Add fast-path for Char.IsDigit in WellKnownFunctions
Copilot Jun 17, 2025
116a6cb
Use char.IsDigit instead of manual ASCII range check
Copilot Jun 17, 2025
fda73b3
Add support for Char.IsDigit(String, Int32) overload with comprehensi…
Copilot Jun 17, 2025
949d5cd
Deduplicate returnVal assignment and return logic for Char.IsDigit ov…
Copilot Jun 18, 2025
c2dbba7
Rewrite PropertyFunctionCharIsDigit test as data-driven Theory using …
Copilot Jun 18, 2025
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25 changes: 25 additions & 0 deletions src/Build.UnitTests/Evaluation/Expander_Tests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -4741,6 +4741,31 @@ public void PropertyFunctionStringArrayGetValue()
TestPropertyFunction("$(X.Split($([System.Convert]::ToString(`.`).ToCharArray())).GetValue($([System.Convert]::ToInt32(0))))", "X", "ab.cd", "ab");
}

/// <summary>
/// Test that Char.IsDigit fast-path works correctly
/// </summary>
[Theory]
// Test with digit characters - single char version
[InlineData("$([System.Char]::IsDigit('0'))", "True")]
[InlineData("$([System.Char]::IsDigit('5'))", "True")]
[InlineData("$([System.Char]::IsDigit('9'))", "True")]
// Test with non-digit characters - single char version
[InlineData("$([System.Char]::IsDigit('a'))", "False")]
[InlineData("$([System.Char]::IsDigit(' '))", "False")]
[InlineData("$([System.Char]::IsDigit('/'))", "False")]
[InlineData("$([System.Char]::IsDigit(':'))", "False")]
// Test with string and index version
[InlineData("$([System.Char]::IsDigit('abc123def', 3))", "True")]
[InlineData("$([System.Char]::IsDigit('abc123def', 4))", "True")]
[InlineData("$([System.Char]::IsDigit('abc123def', 5))", "True")]
[InlineData("$([System.Char]::IsDigit('abc123def', 0))", "False")]
[InlineData("$([System.Char]::IsDigit('abc123def', 2))", "False")]
[InlineData("$([System.Char]::IsDigit('hello789', 5))", "True")]
public void PropertyFunctionCharIsDigit(string expression, string expected)
{
TestPropertyFunction(expression, "dummy", "", expected);
}

private void TestPropertyFunction(string expression, string propertyName, string propertyValue, string expected)
{
var properties = new PropertyDictionary<ProjectPropertyInstance>();
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23 changes: 23 additions & 0 deletions src/Build/Evaluation/Expander/WellKnownFunctions.cs
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Expand Up @@ -875,6 +875,29 @@ internal static bool TryExecuteWellKnownFunction(string methodName, Type receive
}
}
}
else if (receiverType == typeof(char))
{
if (string.Equals(methodName, nameof(char.IsDigit), StringComparison.OrdinalIgnoreCase))
{
bool? result = null;

if (ParseArgs.TryGetArg(args, out string? arg0) && arg0?.Length == 1)
{
char c = arg0[0];
result = char.IsDigit(c);
}
else if (ParseArgs.TryGetArgs(args, out string? str, out int index) && str != null)
{
result = char.IsDigit(str, index);
}

if (result.HasValue)
{
returnVal = result.Value;
return true;
}
}
}
else if (string.Equals(methodName, nameof(Regex.Replace), StringComparison.OrdinalIgnoreCase) && args.Length == 3)
{
if (ParseArgs.TryGetArgs(args, out string? arg1, out string? arg2, out string? arg3) && arg1 != null && arg2 != null && arg3 != null)
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