Handle DelayFree for HW_Category_SIMDByIndexedElement intrinsics

src/coreclr/jit/lsraarm64.cpp

@@ -1481,6 +1481,21 @@ int LinearScan::BuildHWIntrinsic(GenTreeHWIntrinsic* intrinsicTree, int* pDstCou
         {
             srcCount += BuildContainedCselUses(containedCselOp, delayFreeOp, candidates);
         }
+        else if ((intrin.category == HW_Category_SIMDByIndexedElement) && (genTypeSize(intrin.baseType) == 2) && !HWIntrinsicInfo::HasImmediateOperand(intrin.id))
+        {
+            // Some "Advanced SIMD scalar x indexed element" and "Advanced SIMD vector x indexed element" instructions (e.g.
+            // "MLA (by element)") have encoding that restricts what registers that can be used for the indexed element when
+            // the element size is H (i.e. 2 bytes).
+            if (((opNum == 2) || (opNum == 3)))
+            {
+                // For those intrinsics, just force the delay-free registers, so they do not conflict with the definition.
+                srcCount += BuildDelayFreeUses(operand, nullptr, candidates);
+            }
+            else
+            {
+                srcCount += BuildOperandUses(operand, candidates);
+            }
+        }
         // Only build as delay free use if register types match
         else if ((delayFreeOp != nullptr) &&
                  (varTypeUsesSameRegType(delayFreeOp->TypeGet(), operand->TypeGet()) ||

src/tests/JIT/Regression/JitBlue/Runtime_114358/Runtime_114358.cs

@@ -0,0 +1,71 @@
+// 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 206.63 KB to 1.9 KB.
+
+
+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 TestClass_114358
+{
+    public struct S1
+    {
+        public int int_1;
+    }
+    static byte s_byte_4 = 1;
+    static Vector64<short> s_v64_short_20 = Vector64.Create(94, -2, 3, 3);
+    static Vector128<byte> s_v128_byte_28 = Vector128.Create((byte)2);
+    static Vector128<ushort> s_v128_ushort_31 = Vector128.Create((ushort)32766);
+    Vector64<short> v64_short_70 = Vector64<short>.AllBitsSet;
+    Vector128<byte> v128_byte_78 = Vector128.CreateScalar((byte)0);
+    Vector128<short> v128_short_80 = Vector128.Create(-2, 0, 2, 94, 3, 0, 3, 0);
+    Vector128<ushort> v128_ushort_81 = Vector128<ushort>.AllBitsSet;
+    private static List<string> toPrint = new List<string>();
+    internal void Method0()
+    {
+        unchecked
+        {
+            S1 s1_172 = new S1();
+            s_v128_ushort_31 = Vector128.LessThan(s_v128_ushort_31 -= Vector128<ushort>.Zero | v128_ushort_81, AdvSimd.AddWideningUpper(v128_ushort_81 & v128_ushort_81, s_v128_byte_28 = v128_byte_78));
+            v128_short_80 = AdvSimd.ExtractVector128(AdvSimd.MultiplyByScalar(v128_short_80 - v128_short_80, AdvSimd.MultiplySubtractByScalar(v64_short_70, s_v64_short_20, v64_short_70)), v128_short_80 - v128_short_80, s_byte_4);
+            s_v64_short_20 = AdvSimd.ShiftRightLogicalRoundedAdd(v64_short_70 -= v64_short_70 += v64_short_70, v64_short_70 + Vector64<short>.AllBitsSet + v64_short_70 + Vector64<short>.AllBitsSet & v64_short_70, s_byte_4 >>= s1_172.int_1 <<= 15 + 4);
+            return;
+        }
+    }
+
+    [Fact]
+    public static void Repro()
+    {
+        if (AdvSimd.IsSupported)
+        {
+            new TestClass_114358().Method0();
+        }
+    }
+}
+/*
+Environment:
+
+set DOTNET_AltJit=Method0
+set DOTNET_AltJitName=clrjit_universal_arm64_x64.dll
+set DOTNET_EnableWriteXorExecute=0
+set DOTNET_JitDisasm=Method0
+set DOTNET_JitStressRegs=2
+set DOTNET_TieredCompilation=0
+
+Debug: 1639727076
+
+Release: 0
+JIT assert failed:
+Assertion failed '(targetReg == op1Reg) || (targetReg != op3Reg)' in 'TestClass:Method0():this' during 'Generate code' (IL size 298; hash 0x46e9aa75; FullOpts)
+
+    File: /Users/runner/work/1/s/src/coreclr/jit/hwintrinsiccodegenarm64.cpp Line: 416
+
+
+*/

src/tests/JIT/Regression/JitBlue/Runtime_114358/Runtime_114358.csproj

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