usingSystem.Runtime.CompilerServices;publicclassClassA{publicvirtualintGetValue()=>42;}publicclassClassB:ClassA{// we don't even need to override GetValue here}classMyClass{staticvoidMain(){Test(newClassB());}[MethodImpl(MethodImplOptions.NoInlining)]staticintTest(ClassAc)=>c.GetValue();}

Old codegen:

; Method MyClass:Test(ClassA):int (FullOpts)subrsp,40movrax, qword ptr[rcx]call[rax+30H]ClassA:GetValue():int:thisnopaddrsp,40ret; Total bytes of code: 16

New codegen:

00007FF66DD8AFB0cmp         dword ptr[rcx],ecx00007FF66DD8AFB2moveax,2Ah00007FF66DD8AFB7ret

Cc @dotnet/ilc-contrib@EgorBo

Improve getExactClasses to support classes as base types

eb6e2ff

Fixesdotnet#88547```csharpusing System.Runtime.CompilerServices;public class ClassA{    public virtual int GetValue() => 42;}public class ClassB : ClassA{    // we don't even need to override GetValue here}class MyClass{    static void Main()    {        Test(new ClassB());    }    [MethodImpl(MethodImplOptions.NoInlining)]    static int Test(ClassA c) => c.GetValue();}```Old codegen:```; Method MyClass:Test(ClassA):int (FullOpts)       sub      rsp, 40       mov      rax, qword ptr [rcx]       call     [rax+30H]ClassA:GetValue():int:this       nop       add      rsp, 40       ret; Total bytes of code: 16```New codegen:```00007FF66DD8AFB0  cmp         dword ptr [rcx],ecx00007FF66DD8AFB2  mov         eax,2Ah00007FF66DD8AFB7  ret```

MichalStrehovsky added the area-NativeAOT-coreclr label

Sep 21, 2023

ghost assignedMichalStrehovsky

Sep 21, 2023

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ghost commentedSep 21, 2023

Tagging subscribers to this area:@agocke,@MichalStrehovsky,@jkotas
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Issue Details

Fixes#88547

usingSystem.Runtime.CompilerServices;publicclassClassA{publicvirtualintGetValue()=>42;}publicclassClassB:ClassA{// we don't even need to override GetValue here}classMyClass{staticvoidMain(){Test(newClassB());}[MethodImpl(MethodImplOptions.NoInlining)]staticintTest(ClassAc)=>c.GetValue();}

Old codegen:

; Method MyClass:Test(ClassA):int (FullOpts)       sub      rsp, 40       mov      rax, qword ptr [rcx]       call     [rax+30H]ClassA:GetValue():int:this       nop       add      rsp, 40       ret; Total bytes of code: 16

New codegen:

00007FF66DD8AFB0  cmp         dword ptr [rcx],ecx00007FF66DD8AFB2  mov         eax,2Ah00007FF66DD8AFB7  ret

Cc @dotnet/ilc-contrib@EgorBo

Author:	MichalStrehovsky
Assignees:	-
Labels:	`area-NativeAOT-coreclr`
Milestone:	-

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MichalStrehovsky commentedSep 21, 2023

/azp run runtime-nativeaot-outerloop

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azure-pipelinesbot commentedSep 21, 2023

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EgorBo commentedSep 22, 2023

Love it! It should also pick up other jit opts likeif (obj is Class1) or multiple-guesses GDV, etc which currently only kick in for interfaces. LGTM if CI passes 🙂