关于位操作:C#在符号扩展的操作数上使用按位或运算符; 考虑先转换为较小的无符号类型

C# Bitwise-or operator used on a sign-extended operand; consider casting to a smaller unsigned type first

我知道这些警告可能毫无意义。。但是无论如何我都可以摆脱它们吗?

我收到了这些警告中的7条。

Bitwise-or operator used on a sign-extended operand; consider casting to a smaller unsigned type first

这与OR运算符|有关

我强调了发出警告的原因。

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int result = (int)ror((uint)(v76 ^ (v75 | 0x862D63D3)), (uint)(BitConverter.ToInt32(v4, 72) ^ 0x22));

int v11 = (int)rol((uint)(int)((v8 & v10 | ~v10 & 0xEFCDAAC9) + v3[2] - 1126481991), 17);

int v144 = (int)rol((uint)(int)((v141 & v143 | ~v143 & 0xEFCDAAC9) + v3[2] - 1126481991), 17);

int v77 = (int)(`BitConverter.ToInt32(v4, 52) | 0x96C35837`);


BitConverter.GetBytes((int)(v30 & 0x870DEA8A | v29)).CopyTo(v2, 32);

int temp24 |= (int)(BitConverter.ToInt32(v3, 48) | 0x96B4A1B4);

int v17 = (int)(BitConverter.ToInt32(v3, 12) | 0x83868A1D);


快速的网络搜索显示了警告的正式文档,并附带说明:

The compiler implicitly widened and sign-extended a variable, and then
used the resulting value in a bitwise OR operation. This can result in
unexpected behavior.

问题是表达式v75 | 0x862D63D3的格式为int | uint。 通过将双方提升为long来计算。 如果您确实想要符号扩展名,请写(ulong)(long)v75 | 0x862D63D3。 如果您确实想要零扩展名,请编写(uint)v75 |0x862D63D3

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class Program {
 public static void Main()
 {
  int v75 = int.MinValue;
  System.Console.WriteLine("{0:x}", v75 | 0x862D63D3);
  System.Console.WriteLine("{0:x}", (ulong)(long)v75 | 0x862D63D3);
  System.Console.WriteLine("{0:x}", (uint)v75 | 0x862D63D3);
 }
}

该程序打印

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ffffffff862d63d3
ffffffff862d63d3
862d63d3

如您所见,编译器默认使用第一种解释,这可能不是您想要的。


尝试将v75和其他与无符号十六进制值进行或运算的变量转换为uint:

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((uint)v75 | 0x862D63D3)

或将变量声明为uint而不是int


如果对int和long变量执行OR操作,则系统将int转换为long。
存在两种方式:

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namespace ConsoleApplication1
{
class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine($"int.MinValue  = {Convert.ToString(int.MinValue, 2)}");
        Console.WriteLine($"long.MinValue = {Convert.ToString(long.MinValue, 2)}");

        Console.WriteLine();

        long cast1 = int.MinValue;                   // !!!
        long cast2 = unchecked((uint)int.MinValue);  // !!!

        Console.WriteLine($"default cast = {Convert.ToString(cast1, 2)}");
        Console.WriteLine($"custom  cast = {Convert.ToString(cast2, 2)}");

        Console.WriteLine();

        Console.WriteLine($"default long OR int = {Convert.ToString(long.MinValue | int.MinValue, 2)}");
        Console.WriteLine($"custom  long OR int = {Convert.ToString(long.MinValue | unchecked((uint)int.MinValue), 2)}");
}
}

结果:

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int.MinValue  = 10000000000000000000000000000000
long.MinValue = 1000000000000000000000000000000000000000000000000000000000000000

default cast = 1111111111111111111111111111111110000000000000000000000000000000
custom  cast = 0000000000000000000000000000000010000000000000000000000000000000

default long OR int = 1111111111111111111111111111111110000000000000000000000000000000
custom  long OR int = 1000000000000000000000000000000010000000000000000000000000000000

您想要什么结果?