Arm64: Use TYP_SIMD8 for AddAcross (#108727)

* Use TYP_SIMD8 for AddAcross intrinsics

* add test cases

* Mark non interesting method private

* Remove method params

* wrap test code in try-catch

src/coreclr/jit/gentree.cpp

@@ -25602,7 +25602,7 @@ GenTree* Compiler::gtNewSimdSumNode(var_types type, GenTree* op1, CorInfoType si
         case TYP_SHORT:
         case TYP_USHORT:
         {
-            tmp = gtNewSimdHWIntrinsicNode(simdType, op1, NI_AdvSimd_Arm64_AddAcross, simdBaseJitType, simdSize);
+            tmp = gtNewSimdHWIntrinsicNode(TYP_SIMD8, op1, NI_AdvSimd_Arm64_AddAcross, simdBaseJitType, simdSize);
             return gtNewSimdToScalarNode(type, tmp, simdBaseJitType, 8);
         }
 
@@ -25616,7 +25616,7 @@ GenTree* Compiler::gtNewSimdSumNode(var_types type, GenTree* op1, CorInfoType si
             }
             else
             {
-                tmp = gtNewSimdHWIntrinsicNode(TYP_SIMD16, op1, NI_AdvSimd_Arm64_AddAcross, simdBaseJitType, 16);
+                tmp = gtNewSimdHWIntrinsicNode(TYP_SIMD8, op1, NI_AdvSimd_Arm64_AddAcross, simdBaseJitType, 16);
             }
             return gtNewSimdToScalarNode(type, tmp, simdBaseJitType, 8);
         }

src/coreclr/jit/lowerarmarch.cpp

@@ -2611,7 +2611,7 @@ GenTree* Lowering::LowerHWIntrinsicDot(GenTreeHWIntrinsic* node)
             //   ...
 
             tmp2 =
-                comp->gtNewSimdHWIntrinsicNode(simdType, tmp1, NI_AdvSimd_Arm64_AddAcross, simdBaseJitType, simdSize);
+                comp->gtNewSimdHWIntrinsicNode(TYP_SIMD8, tmp1, NI_AdvSimd_Arm64_AddAcross, simdBaseJitType, simdSize);
             BlockRange().InsertAfter(tmp1, tmp2);
             LowerNode(tmp2);
         }

src/tests/JIT/Regression/JitBlue/Runtime_108612/Runtime_108612.cs

@@ -0,0 +1,58 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+// Found by Antigen
+// Reduced from 18.05 KB to 1.2 KB.
+// JIT assert failed:
+// Assertion failed 'm_store->TypeGet() == m_src->TypeGet()' in 'TestClass:Method0():this' during 'Assertion prop' (IL size 91; hash 0x46e9aa75; FullOpts)
+//
+//    File: /Users/runner/work/1/s/src/coreclr/jit/morphblock.cpp Line: 665
+
+
+using System;
+using System.Collections.Generic;
+using System.Runtime.CompilerServices;
+using System.Runtime.Intrinsics;
+using System.Runtime.Intrinsics.Arm;
+using System.Runtime.Intrinsics.X86;
+using System.Numerics;
+using Xunit;
+
+public class Runtime_108612
+{
+    static Vector128<byte> s_v128_byte_27 = Vector128.CreateScalar((byte)0);
+    static Vector128<int> s_v128_int_31 = Vector128<int>.Zero;
+    static Vector128<uint> s_v128_uint_32 = Vector128.CreateScalar((uint)5);
+    Vector64<byte> v64_byte_67 = Vector64.CreateScalar((byte)5);
+    Vector128<int> v128_int_81 = Vector128.Create(-1, 6, 2, 1);
+    private static List<string> toPrint = new List<string>();
+    private void Method0()
+    {
+        unchecked
+        {
+            v128_int_81 = AdvSimd.NegateSaturate(s_v128_int_31 *= 15|4);
+            s_v128_uint_32 = AdvSimd.ShiftRightLogicalRounded(s_v128_uint_32, Vector128.Sum(s_v128_byte_27 | s_v128_byte_27));
+            v64_byte_67 = AdvSimd.Arm64.AddAcross(s_v128_byte_27 | s_v128_byte_27);
+            return;
+        }
+    }
+
+    [Fact]
+    public static void TestEntryPoint()
+    {
+        if (AdvSimd.IsSupported)
+        {
+            Antigen();
+        }
+    }
+
+    private static int Antigen()
+    {
+        try
+        {
+            new Runtime_108612().Method0();
+        }
+        catch (Exception e) { }
+        return string.Join(Environment.NewLine, toPrint).GetHashCode();
+    }
+}

src/tests/JIT/Regression/JitBlue/Runtime_108612/Runtime_108612.csproj

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