讓他們看,易圖,一出
,你可以在這兩個,調試/發行版本看到的,給幾乎相同的結果。
的第二種方法,它會創建一個臨時變量,將做完全一樣,你對你的第一個方法
DEBUG方法一(第一個代碼段)
.method private hidebysig static
void Method1() cil managed
{
// Method begins at RVA 0x2060
// Code size 23 (0x17)
.maxstack 2
.locals init (
[0] int32 x,
[1] int32 y,
[2] int32 z
)
IL_0000: nop
IL_0001: ldc.i4.5
IL_0002: stloc.0
IL_0003: ldc.i4.7
IL_0004: stloc.1
IL_0005: ldloc.0
IL_0006: ldloc.1
IL_0007: add
IL_0008: stloc.2
IL_0009: ldloca.s z
IL_000b: call instance string [mscorlib]System.Int32::ToString()
IL_0010: call void [mscorlib]System.Console::Write(string)
IL_0015: nop
IL_0016: ret
} // end of method Program::Method1
DEBUG的Int32 z = x+y;
Method2(Second code snippet)
.method private hidebysig static
void Method2() cil managed
{
// Method begins at RVA 0x2084
// Code size 23 (0x17)
.maxstack 2
.locals init (
[0] int32 x,
[1] int32 y,
[2] int32 CS$0$0000
)
IL_0000: nop
IL_0001: ldc.i4.5
IL_0002: stloc.0
IL_0003: ldc.i4.7
IL_0004: stloc.1
IL_0005: ldloc.0
IL_0006: ldloc.1
IL_0007: add
IL_0008: stloc.2
IL_0009: ldloca.s CS$0$0000
IL_000b: call instance string [mscorlib]System.Int32::ToString()
IL_0010: call void [mscorlib]System.Console::Write(string)
IL_0015: nop
IL_0016: ret
} // end of method Program::Method2
RELEASE Method1(Fir ST代碼段)
.method private hidebysig static
void Method1() cil managed
{
// Method begins at RVA 0x205c
// Code size 21 (0x15)
.maxstack 2
.locals init (
[0] int32 x,
[1] int32 y,
[2] int32 z
)
IL_0000: ldc.i4.5
IL_0001: stloc.0
IL_0002: ldc.i4.7
IL_0003: stloc.1
IL_0004: ldloc.0
IL_0005: ldloc.1
IL_0006: add
IL_0007: stloc.2
IL_0008: ldloca.s z
IL_000a: call instance string [mscorlib]System.Int32::ToString()
IL_000f: call void [mscorlib]System.Console::Write(string)
IL_0014: ret
} // end of method Program::Method1
RELEASE方法2(第二代碼片段)
.method private hidebysig static
void Method2() cil managed
{
// Method begins at RVA 0x2080
// Code size 21 (0x15)
.maxstack 2
.locals init (
[0] int32 x,
[1] int32 y,
[2] int32 CS$0$0000
)
IL_0000: ldc.i4.5
IL_0001: stloc.0
IL_0002: ldc.i4.7
IL_0003: stloc.1
IL_0004: ldloc.0
IL_0005: ldloc.1
IL_0006: add
IL_0007: stloc.2
IL_0008: ldloca.s CS$0$0000
IL_000a: call instance string [mscorlib]System.Int32::ToString()
IL_000f: call void [mscorlib]System.Console::Write(string)
IL_0014: ret
} // end of method Program::Method2
,直到你有_real_性能問題不要擔心(可能)浪費納秒。儘量編寫清晰且可維護的代碼。 – HABO
您不指定您正在調查此問題的編譯器,運行時或目標平臺。 –
不要試圖「幫助」編譯器。任何半面體優化JIT都會將你的小片段縮減爲相當於Console.Write(「12」)。將CIL代碼轉換爲JIT的中間表示形式時,最有可能丟棄表達式是否存儲在變量中的信息。 –