JIT: Assertion failed 'false && "found use of a node that is not in the LIR sequence"' during 'Lowering nodeinfo'

[jakobbotsch]

// Generated by Fuzzlyn v3.3 on 2026-03-08 16:41:49
// Run on Arm64 MacOS
// Seed: 9286072369653102690-vectort,vector64,vector128,armadvsimd,armadvsimdarm64,armaes,armarmbase,armarmbasearm64,armcrc32,armcrc32arm64,armdp,armrdm,armrdmarm64,armsha1,armsha256
// Reduced from 299.3 KiB to 0.3 KiB in 00:02:44
// Hits JIT assert for Release:
// Assertion failed 'false && "found use of a node that is not in the LIR sequence"' in 'Program:M4():int' during 'Lowering nodeinfo' (IL size 30; hash 0xadbe37fa; FullOpts)
// 
//     File: /Users/runner/work/1/s/src/coreclr/jit/lir.cpp Line: 1686
// 
public class Program
{
    public static long[] s_1 = new long[]
    {
        0
    };
    public static void Main()
    {
        bool vr5 = M4() == s_1[0];
    }

    public static int M4()
    {
        if ((ushort)(s_1[0] & 3245280089U) > -1L)
        {
            var vr2 = s_1[0];
        }

        return 1;
    }
}

Bisected to #124601, cc @jonathandavies-arm

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[jakobbotsch]

Another case bisected to #124601:

// Generated by Fuzzlyn v3.3 on 2026-03-08 16:30:55
// Run on Arm64 MacOS
// Seed: 10562635396882260649-vectort,vector64,vector128,armadvsimd,armadvsimdarm64,armaes,armarmbase,armarmbasearm64,armcrc32,armcrc32arm64,armdp,armrdm,armrdmarm64,armsha1,armsha256
// Reduced from 120.5 KiB to 0.4 KiB in 00:01:43
// Hits JIT assert for Release:
// Assertion failed '!HAS_FIXED_REGISTER_SET || arg->OperIsPutArg()' in 'Program:M9(short):int' during 'Lowering nodeinfo' (IL size 52; hash 0x4c4f6f25; FullOpts)
// 
//     File: /Users/runner/work/1/s/src/coreclr/jit/lower.cpp Line: 9406
// 
public class Program
{
    public static short s_6;
    public static void Main()
    {
        M9(s_6);
    }

    public static int M9(short arg0)
    {
        ushort[] var1 = new ushort[]
        {
            1
        };
        bool var2 = (0 >> var1[0]) <= (long)(s_6 & 1);
        System.Console.WriteLine(var2);
        return 1;
    }
}