JIT: Don't assume unsigned arithmetic always produces non-negative result in value numbering (#109384)

Fixes #109337.

Author: amanasifkhalid

src/coreclr/jit/valuenum.cpp

@@ -6553,6 +6553,16 @@ bool ValueNumStore::IsVNInt32Constant(ValueNum vn)
     return TypeOfVN(vn) == TYP_INT;
 }
 
+//------------------------------------------------------------------------
+// IsVNNeverNegative: Determines if the given value number can never take on a negative value
+// in a signed context (i.e. when the most-significant bit represents signedness).
+//
+// Parameters:
+//    vn - Value number to query
+//
+// Returns:
+//    True if the most-significant bit is never set, false otherwise.
+//
 bool ValueNumStore::IsVNNeverNegative(ValueNum vn)
 {
     auto vnVisitor = [this](ValueNum vn) -> VNVisit {
@@ -6595,15 +6605,10 @@ bool ValueNumStore::IsVNNeverNegative(ValueNum vn)
                 case VNF_LE:
                 case VNF_EQ:
                 case VNF_NE:
-                case VNF_UMOD:
-                case VNF_UDIV:
                 case VNF_GE_UN:
                 case VNF_GT_UN:
                 case VNF_LE_UN:
                 case VNF_LT_UN:
-                case VNF_ADD_UN_OVF:
-                case VNF_SUB_UN_OVF:
-                case VNF_MUL_UN_OVF:
                 case VNF_MDArrLowerBound:
 #ifdef FEATURE_HW_INTRINSICS
 #ifdef TARGET_XARCH

src/tests/JIT/Regression/JitBlue/Runtime_109337/Runtime_109337.cs

@@ -0,0 +1,49 @@
+// 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 v2.4 on 2024-10-27 16:58:11
+// Run on X86 Windows
+// Seed: 13886187988830061152-vectort,vector128,vector256,x86aes,x86avx,x86avx2,x86avx512bw,x86avx512bwvl,x86avx512cd,x86avx512cdvl,x86avx512dq,x86avx512dqvl,x86avx512f,x86avx512fvl,x86bmi1,x86bmi2,x86fma,x86lzcnt,x86pclmulqdq,x86popcnt,x86sse,x86sse2,x86sse3,x86sse41,x86sse42,x86ssse3,x86x86base
+// Reduced from 241.5 KiB to 0.6 KiB in 00:05:21
+// Debug: Prints 0 line(s)
+// Release: Prints 1 line(s)
+using Xunit;
+
+public class Runtime_109337
+{
+    private struct S0
+    {
+        public uint F1;
+        public ushort F2;
+    }
+
+    [Fact]
+    public static void TestEntryPoint()
+    {
+        var vr4 = new S0();
+        Assert.Equal(0, TestDiv(vr4));
+
+        vr4.F1 = 2147483649u;
+        Assert.Equal(0, TestMod(vr4));
+    }
+
+    private static int TestDiv(S0 argThis)
+    {
+        if (((long)(17731708739983220386UL / (ushort)(argThis.F2 | 1))) >= 0)
+        {
+            return 1;
+        }
+
+        return 0;
+    }
+
+    private static int TestMod(S0 argThis)
+    {
+        if (((int)(2147483648u % argThis.F1)) >= 0)
+        {
+            return 1;
+        }
+
+        return 0;
+    }
+}

src/tests/JIT/Regression/JitBlue/Runtime_109337/Runtime_109337.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <Optimize>True</Optimize>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildProjectName).cs" />
+  </ItemGroup>
+</Project>