Fix 'x < 0' for unsigned (#83656)

Author: TIHan

src/coreclr/jit/codegenarm64.cpp

@@ -4536,7 +4536,8 @@ void CodeGen::genCodeForCompare(GenTreeOp* tree)
             regNumber op1Reg = op1->GetRegNum();
 
             if (compiler->opts.OptimizationEnabled() && (ins == INS_cmp) && (targetReg != REG_NA) &&
-                tree->OperIs(GT_LT) && intConst->IsIntegralConst(0) && ((cmpSize == EA_4BYTE) || (cmpSize == EA_8BYTE)))
+                tree->OperIs(GT_LT) && !tree->IsUnsigned() && intConst->IsIntegralConst(0) &&
+                ((cmpSize == EA_4BYTE) || (cmpSize == EA_8BYTE)))
             {
                 emit->emitIns_R_R_I(INS_lsr, cmpSize, targetReg, op1Reg, (int)cmpSize * 8 - 1);
                 genProduceReg(tree);

src/tests/JIT/opt/Regressions/Regression7.cs

@@ -0,0 +1,28 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+// Generated by Fuzzlyn v1.5 on 2023-03-19 17:44:38
+// Run on Arm64 Linux
+// Seed: 516098027771570682
+public class C0
+{
+    public uint F1;
+    public C0(uint f1)
+    {
+        F1 = f1;
+    }
+}
+
+public class Program
+{
+    // This test was testing an ARM64 regression when optimizing 'x < 0' when it didn't take into account an unsigned operation.
+    public static int Main()
+    {
+        var vr1 = new C0(4294967295U);
+        bool vr3 = !(vr1.F1 > -1);
+        if (!vr3)
+            return 100;
+        else
+            return 0;
+    }
+}

src/tests/JIT/opt/Regressions/Regression7.csproj

@@ -0,0 +1,12 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+  </PropertyGroup>
+  <PropertyGroup>
+    <DebugType>None</DebugType>
+    <Optimize>True</Optimize>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildProjectName).cs" />
+  </ItemGroup>
+</Project>