JIT: Local morph GetElement/WithElement handling for Vector3 does not handle larger SIMD sources

[jakobbotsch]

[MethodImpl(MethodImplOptions.NoInlining)]
private static Vector3 Foo(Vector256<byte> v)
{
    return Unsafe.As<Vector256<byte>, Vector3>(ref v);
}

Result:

Assert failure(PID 27156 [0x00006a14], Thread: 46384 [0xb530]): Assertion failed 'genTypeSize(varDsc) == 16' in 'Program:Foo(System.Runtime.Intrinsics.Vector256`1[ubyte]):System.Numerics.Vector3' during 'Morph - Structs/AddrExp' (IL size 13; hash 0xf577d4ba; FullOpts)

    File: C:\dev\dotnet\runtime\src\coreclr\jit\lclmorph.cpp Line: 948
    Image: C:\dev\dotnet\runtime4\artifacts\tests\coreclr\windows.x64.Checked\Tests\Core_Root\corerun.exe

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Issue Details

---

[MethodImpl(MethodImplOptions.NoInlining)]
private static Vector3 Foo(Vector256<byte> v)
{
    return Unsafe.As<Vector256<byte>, Vector3>(ref v);
}

Result:

Assert failure(PID 27156 [0x00006a14], Thread: 46384 [0xb530]): Assertion failed 'genTypeSize(varDsc) == 16' in 'Program:Foo(System.Runtime.Intrinsics.Vector256`1[ubyte]):System.Numerics.Vector3' during 'Morph - Structs/AddrExp' (IL size 13; hash 0xf577d4ba; FullOpts)

    File: C:\dev\dotnet\runtime\src\coreclr\jit\lclmorph.cpp Line: 948
    Image: C:\dev\dotnet\runtime4\artifacts\tests\coreclr\windows.x64.Checked\Tests\Core_Root\corerun.exe

Author:	jakobbotsch
Assignees:	-
Labels:	area-CodeGen-coreclr
Milestone:	-