Do not enregister Return SP check variable

[kunalspathak]

Antigen found an issue that when COMPlus_JitStackChecks=1 was used, we hit the following assert. The ReturnSpCheck should be marked as DoNotEnregister.

Assert failure(PID 51312 [0x0000c870], Thread: 49364 [0xc0d4]): Assertion failed 'lvaStackPointerVar != 0xCCCCCCCC && compiler->lvaTable[lvaStackPointerVar].lvDoNotEnregister && compiler->lvaTable[lvaStackPointerVar].lvOnFrame' in 'ILStubClass:IL_STUB_ReversePInvoke(long,int,ubyte,long,long,long,long)' during 'Generate code' (IL size 98)

    File: D:\git\runtime\src\coreclr\jit\codegencommon.cpp Line: 11699
    Image: D:\git\runtime\artifacts\tests\coreclr\windows.x64.Checked\tests\Core_Root\corerun.exe

[kunalspathak]

@dotnet/jit-contrib

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Issue Details

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Antigen found an issue that when COMPlus_JitStackChecks=1 was used, we hit the following assert. The ReturnSpCheck should be marked as DoNotEnregister.

Assert failure(PID 51312 [0x0000c870], Thread: 49364 [0xc0d4]): Assertion failed 'lvaStackPointerVar != 0xCCCCCCCC && compiler->lvaTable[lvaStackPointerVar].lvDoNotEnregister && compiler->lvaTable[lvaStackPointerVar].lvOnFrame' in 'ILStubClass:IL_STUB_ReversePInvoke(long,int,ubyte,long,long,long,long)' during 'Generate code' (IL size 98)

    File: D:\git\runtime\src\coreclr\jit\codegencommon.cpp Line: 11699
    Image: D:\git\runtime\artifacts\tests\coreclr\windows.x64.Checked\tests\Core_Root\corerun.exe

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

[kunalspathak]

Failures seems to be unrelated.