Fix two latent HWIntrinsic miscompiles in gentree.cpp

src/coreclr/jit/gentree.cpp

@@ -25982,9 +25982,6 @@ GenTree* Compiler::gtNewSimdMinMaxNode(var_types type,
                         needsFixup = cnsNode->IsFloatNegativeZero();
                     }
                     else
-                    {
-                        needsFixup = cnsNode->IsVectorZero();
-                    }
                     {
                         needsFixup = cnsNode->IsVectorNegativeZero(simdBaseType);
                     }
@@ -31103,7 +31100,7 @@ genTreeOps GenTreeHWIntrinsic::GetOperForHWIntrinsicId(bool* isScalar, bool getE
                 {
                     oper = GT_NEG;
                 }
-                else if (isScalar && op1->IsCnsVec() && op1->AsVecCon()->IsScalarZero(simdBaseType))
+                else if (*isScalar && op1->IsCnsVec() && op1->AsVecCon()->IsScalarZero(simdBaseType))
                 {
                     oper = GT_NEG;
                 }

src/tests/JIT/Regression/JitBlue/Runtime_130830/Runtime_130830.cs

@@ -0,0 +1,27 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Runtime_130830;
+
+using System.Runtime.CompilerServices;
+using System.Runtime.Intrinsics;
+using Xunit;
+
+public static class Runtime_130830
+{
+    [Fact]
+    public static void TestEntryPoint()
+    {
+        Vector128<int> result = Test(Vector128.Create(10), Vector128.Create(100));
+        Assert.Equal(Vector128.Create(90, 91, 92, 93), result);
+    }
+
+    // The low lane of the constant is zero but the constant is not all-zero, so the
+    // subtract must not be treated as a negate; otherwise the constant is dropped and
+    // the result collapses to <90, 90, 90, 90>.
+    [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+    private static Vector128<int> Test(Vector128<int> v1, Vector128<int> v2)
+    {
+        return (Vector128.Create(0, 1, 2, 3) - v1) + v2;
+    }
+}

src/tests/JIT/Regression/JitBlue/Runtime_130831/Runtime_130831.cs

@@ -0,0 +1,36 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Runtime_130831;
+
+using System;
+using System.Runtime.CompilerServices;
+using Xunit;
+
+public static class Runtime_130831
+{
+    // Compare the exact bit pattern: Double/Single.Equals treat -0.0 and +0.0 as equal,
+    // so a plain Assert.Equal would not observe a wrong-signed-zero result.
+    [Fact]
+    [SkipOnMono("https://github.com/dotnet/runtime/issues/131130", TestPlatforms.Any)]
+    public static void TestEntryPoint()
+    {
+        Assert.Equal(BitConverter.DoubleToInt64Bits(-0.0), BitConverter.DoubleToInt64Bits(MinNegZeroConst(+0.0)));
+        Assert.Equal(BitConverter.DoubleToInt64Bits(-0.0), BitConverter.DoubleToInt64Bits(MinNumberZeroConst(-0.0)));
+
+        Assert.Equal(BitConverter.SingleToInt32Bits(-0.0f), BitConverter.SingleToInt32Bits(MinNegZeroConst(+0.0f)));
+        Assert.Equal(BitConverter.SingleToInt32Bits(-0.0f), BitConverter.SingleToInt32Bits(MinNumberZeroConst(-0.0f)));
+    }
+
+    [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+    private static double MinNegZeroConst(double value) => double.Min(value, -0.0);
+
+    [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+    private static double MinNumberZeroConst(double value) => double.MinNumber(value, +0.0);
+
+    [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+    private static float MinNegZeroConst(float value) => float.Min(value, -0.0f);
+
+    [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+    private static float MinNumberZeroConst(float value) => float.MinNumber(value, +0.0f);
+}

src/tests/JIT/Regression/Regression_ro_2.csproj

@@ -114,6 +114,8 @@
     <Compile Include="JitBlue\Runtime_130248\Runtime_130248.cs" />
     <Compile Include="JitBlue\Runtime_130286\Runtime_130286.cs" />
     <Compile Include="JitBlue\Runtime_130425\Runtime_130425.cs" />
+    <Compile Include="JitBlue\Runtime_130830\Runtime_130830.cs" />
+    <Compile Include="JitBlue\Runtime_130831\Runtime_130831.cs" />
     <Compile Include="JitBlue\Runtime_10337\Runtime_10337.cs" />
     <Compile Include="JitBlue\Runtime_125160\Runtime_125160.cs" />
   </ItemGroup>