akeit0 · August 28, 2024 05:32
diff --git a/IncrementTest.cs b/IncrementTest.cs
 using System;
 public class Test
 {
    struct Struct()
    {
        public int A = 0;
    }

    public int IncrementSlow()
    {
        var a = new Struct();
        for (int i = 0; i < 100; i++)
        {
            a.A++;
            a.A++;
        }

        return a.A;
    }

    public int IncrementFast()
    {
        var a = new Struct();
        for (int i = 0; i < 100; i++)
        {
            a= new Struct(){A = a.A + 1};
            a= new Struct(){A = a.A + 1};
        }

        return a.A;
    }
 }
diff --git a/IncrementTest.jit.asm b/IncrementTest.jit.asm
 ; Core CLR 8.0.724.31311 on x64

 Test..ctor()
    L0000: ret

 Test.IncrementSlow()
    L0000: xor eax, eax
    L0002: xor ecx, ecx
    L0004: add eax, 2
    L0007: inc ecx
    L0009: cmp ecx, 0x64
    L000c: jl short L0004
    L000e: ret

 Test.IncrementFast()
    L0000: xor eax, eax
    L0002: xor ecx, ecx
    L0004: inc eax
    L0006: inc eax
    L0008: inc ecx
    L000a: cmp ecx, 0x64
    L000d: jl short L0004
    L000f: ret

 Test+Struct..ctor()
    L0000: xor eax, eax
    L0002: mov [rcx], eax
    L0004: ret
diff --git a/.sharplab.json b/.sharplab.json
 {
    "version": 1,
    "target": "JIT ASM",
    "mode": "Release",
    "branch": "core-x64"
 }
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