Consider making Interlocked.And and friends into JIT intrinsics

[stephentoub]

From #32216 (comment)

#32216 adds new methods like Interlocked.And. Some of these could be done as JIT intrinsics and replaced by better implementations/instructions in some cases, like lock and on platforms that have it.

cc: @tannergooding

category:cq
theme:jit-intrinsics
skill-level:intermediate
cost:medium
impact:medium

[BruceForstall]

@AndyAyersMS

[GrabYourPitchforks]

For context, it turns out the JIT already optimizes this for the existing Interlocked.Add and similar APIs.

using System;
using System.Threading;

public class C {
    public static int M(ref int i) {
        return Interlocked.Add(ref i, 1);
    }
    
    public static void N(ref int i) {
        Interlocked.Add(ref i, 1);
    }
}

; C.M(Int32 ByRef)
    L0000: mov eax, 0x1
    L0005: lock xadd [rcx], eax
    L0009: inc eax
    L000b: ret

; C.N(Int32 ByRef)
    L0000: lock add dword [rcx], 0x1
    L0004: ret

[stephentoub]

Nice. This can be closed then, right?

Oh.. you said Add, not And. Those are way too closely named :-) I was very impressed it was able to reverse the pattern in Interlocked.And :-)

[AndyAyersMS]

These should be done via new-style intrinsics. We may also want to convert some of the existing intrinsified interlocked ops over to this mechanism as well.

[AndyAyersMS]

@Stoub we're triaging proposed 5.0 codegen work -- any thoughts on the priority of this issue?

[stephentoub]

From my perspective, "nice to have", but I expect there's other higher priority JIT work that'll be more impactful. These APIs are brand new.