[llvm-bugs] [Bug 46595] New: Add _InterlockedIncrement64 and other intrinsic for x86 for parity with MSVC

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=46595

            Bug ID: 46595
           Summary: Add _InterlockedIncrement64 and other intrinsic for
                    x86 for parity with MSVC
           Product: clang
           Version: 10.0
          Hardware: PC
                OS: Windows NT
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: -New Bugs
          Assignee: unassignedclangbugs at nondot.org
          Reporter: gutenev at gmail.com
                CC: htmldeveloper at gmail.com, llvm-bugs at lists.llvm.org,
                    neeilans at live.com, richard-llvm at metafoo.co.uk

The following intrinsic functions were recently added to MSVC for x86:

__MACHINE(__int64 _InterlockedAnd64(__int64 volatile * _Value, __int64 _Mask))
__MACHINE(__int64 _InterlockedDecrement64(__int64 volatile * _Addend))
__MACHINE(__int64 _InterlockedExchange64(__int64 volatile * _Target, __int64
_Value))
__MACHINE(__int64 _InterlockedExchangeAdd64(__int64 volatile * _Addend, __int64
_Value))
__MACHINE(__int64 _InterlockedIncrement64(__int64 volatile * _Addend))
__MACHINE(__int64 _InterlockedOr64(__int64 volatile * _Value, __int64 _Mask))
__MACHINE(__int64 _InterlockedXor64(__int64 volatile * _Value, __int64 _Mask))

They are implemented using lock cmpxchg8b. However, this implementation is
still expected to be more efficient than direct _InterlockedCompareExchange64


The following are exact steps to see the absence of _InterlockedIncrement64 
 on x86 in clang-cl:


d:\Temp2>"C:\Program Files (x86)\Microsoft Visual
Studio\2019\Preview\VC\Tools\MSVC\14.27.29009\bin\Hostx86\x86\cl.exe"
Microsoft (R) C/C++ Optimizing Compiler Version 19.27.29009.1 for x86
Copyright (C) Microsoft Corporation.  All rights reserved.

usage: cl [ option... ] filename... [ /link linkoption... ]

d:\Temp2>"C:\Program Files (x86)\Microsoft Visual
Studio\2019\Preview\VC\Tools\Llvm\bin\clang-cl.exe" --version
clang version 10.0.0
Target: i686-pc-windows-msvc
Thread model: posix
InstalledDir: C:\Program Files (x86)\Microsoft Visual
Studio\2019\Preview\VC\Tools\Llvm\bin

d:\Temp2>type repro.cpp
#include <intrin.h>

volatile long long i = 0;

int main()
{
    _InterlockedIncrement64(&i);
}


d:\Temp2>"C:\Program Files (x86)\Microsoft Visual
Studio\2019\Preview\VC\Tools\MSVC\14.27.29009\bin\Hostx86\x86\cl.exe" repro.cpp
Microsoft (R) C/C++ Optimizing Compiler Version 19.27.29009.1 for x86
Copyright (C) Microsoft Corporation.  All rights reserved.

repro.cpp
Microsoft (R) Incremental Linker Version 14.27.29009.1
Copyright (C) Microsoft Corporation.  All rights reserved.

/out:repro.exe
repro.obj

d:\Temp2>"C:\Program Files (x86)\Microsoft Visual
Studio\2019\Preview\VC\Tools\Llvm\bin\clang-cl.exe" repro.cpp
repro.cpp(7,5): error: use of undeclared identifier '_InterlockedIncrement64'
    _InterlockedIncrement64(&i);
    ^
1 error generated.

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