C# と VB.NET の質問掲示板

■No101282 (ぼんど  さん) に返信
> それなら、変数の型の種類によらないと思うのですが、
> なぜ整数型の場合には違いが見られなくなるのでしょうか？

検証コードが間違っているのでは？
手元でやってみましたが、２倍以上違います。

Module Module1

    Public Structure PointF_3DF
        Public X As Integer
        Public Y As Integer
        Public Z As Integer
    End Structure

    Public Structure PointF_3DP
        Property X As Integer
        Property Y As Integer
        Property Z As Integer
    End Structure

    Sub Main()
        Dim ss As New Stopwatch
        Dim hh As Integer = 100000000
        Dim aa(hh) As PointF_3DF
        Dim bb(hh) As PointF_3DP
        Dim RefVal1 As New PointF_3DF With {.X = 1, .Y = 2, .Z = 3}
        Dim RefVal2 As New PointF_3DP With {.X = 1, .Y = 2, .Z = 3}

        ss.Restart()
        For i = 0 To hh
            aa(i).X = RefVal1.X
            aa(i).Y = RefVal1.Y
            aa(i).Z = RefVal1.Z
        Next
        MsgBox(ss.ElapsedMilliseconds)

        ss.Restart()
        For i = 0 To hh
            bb(i).X = RefVal2.X
            bb(i).Y = RefVal2.Y
            bb(i).Z = RefVal2.Z
        Next
        MsgBox(ss.ElapsedMilliseconds)
    End Sub

End Module

https://sharplab.io で、簡単な検証用ソースのアセンブリコードを比較してみました。

----------------
Imports System
Imports System.Diagnostics
Imports System.Runtime.CompilerServices

Module Module1

    Public Structure PointF_3DF
        Public X As Integer
        Public Y As Integer
        Public Z As Integer
        Public Function Sum() As Integer
            Return X + Y + Z
        End Function
    End Structure

    Public Structure PointF_3DP
        Property X As Integer
        Property Y As Integer
        Property Z As Integer
        Public Function Sum() As Integer
            Return X + Y + Z
        End Function
        <MethodImpl(MethodImplOptions.AggressiveInlining)>
        Public Function Sum2() As Integer
            Return X + Y + Z
        End Function
    End Structure

    Sub Calc1()
        Dim v = Create3DF()
        Console.WriteLine(v.Sum())
    End Sub

    Sub Calc2()
        Dim v = Create3DP()
        Console.WriteLine(v.Sum())
    End Sub

    Sub Calc3()
        Dim v = Create3DP()
        Console.WriteLine(v.Sum2())
    End Sub

    Function Create3DF() As PointF_3DF
        Static r As New Random
        Const Max = 100           
        Return New PointF_3DF() With {.X = r.Next(1, Max), .Y = r.Next(1, Max), .Z = r.Next(1, Max)}
    End Function

    Function Create3DP() As PointF_3DP
        Static r As New Random
        Const Max = 100           
        Return New PointF_3DP() With {.X = r.Next(1, Max), .Y = r.Next(1, Max), .Z = r.Next(1, Max)}
    End Function

End Module
----------------


[x64 Release]
; Core CLR 7.0.22.51805 on x64

Module1.Calc1()
    L0000: sub rsp, 0x38
    L0004: xor eax, eax
    L0006: mov [rsp+0x28], rax
    L000b: mov [rsp+0x30], rax
    L0010: lea rcx, [rsp+0x28]
    L0015: call 0x00007ff9b0ee0048
    L001a: mov ecx, [rsp+0x28]
    L001e: add ecx, [rsp+0x2c]
    L0022: jo short L003c
    L0024: add ecx, [rsp+0x30]
    L0028: jo short L003c
    L002a: mov rax, 0x7ff9644a9b70
    L0034: call qword ptr [rax]
    L0036: nop
    L0037: add rsp, 0x38
    L003b: ret
    L003c: call 0x00007ff9c30c8710
    L0041: int3

Module1.Calc2()
    L0000: sub rsp, 0x38
    L0004: xor eax, eax
    L0006: mov [rsp+0x28], rax
    L000b: mov [rsp+0x30], rax
    L0010: lea rcx, [rsp+0x28]
    L0015: call 0x00007ff9b0ee0060
    L001a: mov ecx, [rsp+0x28]
    L001e: add ecx, [rsp+0x2c]
    L0022: jo short L003c
    L0024: add ecx, [rsp+0x30]
    L0028: jo short L003c
    L002a: mov rax, 0x7ff9644a9b70
    L0034: call qword ptr [rax]
    L0036: nop
    L0037: add rsp, 0x38
    L003b: ret
    L003c: call 0x00007ff9c30c8710
    L0041: int3

Module1.Calc3()
    L0000: sub rsp, 0x38
    L0004: xor eax, eax
    L0006: mov [rsp+0x28], rax
    L000b: mov [rsp+0x30], rax
    L0010: lea rcx, [rsp+0x28]
    L0015: call 0x00007ff9b0ee0060
    L001a: mov ecx, [rsp+0x28]
    L001e: add ecx, [rsp+0x2c]
    L0022: jo short L003c
    L0024: add ecx, [rsp+0x30]
    L0028: jo short L003c
    L002a: mov rax, 0x7ff9644a9b70
    L0034: call qword ptr [rax]
    L0036: nop
    L0037: add rsp, 0x38
    L003b: ret
    L003c: call 0x00007ff9c30c8710
    L0041: int3


[.NET Framework x64 Release]
; Desktop CLR 4.8.4526.0 on amd64

Module1.Calc1()
    L0000: sub rsp, 0x38
    L0004: xor eax, eax
    L0006: mov [rsp+0x28], rax
    L000b: mov [rsp+0x30], rax
    L0010: lea rcx, [rsp+0x28]
    L0015: call Module1.Create3DF()
    L001a: mov ecx, [rsp+0x28]
    L001e: add ecx, [rsp+0x2c]
    L0022: jo L0035
    L0024: add ecx, [rsp+0x30]
    L0028: jo L0035
    L002a: call System.Console.WriteLine(Int32)
    L002f: nop
    L0030: add rsp, 0x38
    L0034: ret
    L0035: call 0x7ff9e6ae9090
    L003a: int3

Module1.Calc2()
    L0000: sub rsp, 0x38
    L0004: xor eax, eax
    L0006: mov [rsp+0x28], rax
    L000b: mov [rsp+0x30], rax
    L0010: lea rcx, [rsp+0x28]
    L0015: call Module1.Create3DP()
    L001a: lea rcx, [rsp+0x28]
    L001f: call Module1+PointF_3DP.Sum()
    L0024: mov ecx, eax
    L0026: call System.Console.WriteLine(Int32)
    L002b: nop
    L002c: add rsp, 0x38
    L0030: ret

Module1.Calc3()
    L0000: sub rsp, 0x38
    L0004: xor eax, eax
    L0006: mov [rsp+0x28], rax
    L000b: mov [rsp+0x30], rax
    L0010: lea rcx, [rsp+0x28]
    L0015: call Module1.Create3DP()
    L001a: mov ecx, [rsp+0x28]
    L001e: add ecx, [rsp+0x2c]
    L0022: jo L0035
    L0024: add ecx, [rsp+0x30]
    L0028: jo L0035
    L002a: call System.Console.WriteLine(Int32)
    L002f: nop
    L0030: add rsp, 0x38
    L0034: ret
    L0035: call 0x7ff9e6ae9090
    L003a: int3


.NET Frameworkだと、プロパティがインライン展開されていないですね。
その場合でも、AggressiveInlining指定で同じようなコードが出力されました。
このように、最適化はフレームワーク等の条件で変化する可能性もあるので、
動作環境や計測方法のソースを記述した方がよろしいかと思います。
理論上は遅くなりそうなソースでも、
実際は最適化によって殆ど変わらないというケースも十分ありえます。