JIT: Remove GT_CAST handling in Lowering::IsValidConstForMovImm (#…

…106092)

src/coreclr/jit/lowerarmarch.cpp

@@ -1919,8 +1919,6 @@ GenTree* Lowering::LowerHWIntrinsic(GenTreeHWIntrinsic* node)
 //  Returns:
 //     true if the node can be replaced by a mov/fmov immediate instruction; otherwise, false
 //
-//  IMPORTANT:
-//     This check may end up modifying node->gtOp1 if it is a cast node that can be removed
 bool Lowering::IsValidConstForMovImm(GenTreeHWIntrinsic* node)
 {
     assert((node->GetHWIntrinsicId() == NI_Vector64_Create) || (node->GetHWIntrinsicId() == NI_Vector128_Create) ||
@@ -1934,51 +1932,16 @@ bool Lowering::IsValidConstForMovImm(GenTreeHWIntrinsic* node)
            (node->GetHWIntrinsicId() == NI_AdvSimd_Arm64_DuplicateToVector128));
     assert(node->GetOperandCount() == 1);
 
-    GenTree* op1    = node->Op(1);
-    GenTree* castOp = nullptr;
-
-    // TODO-Casts: why don't we fold the casts? MinOpts?
-    if (varTypeIsIntegral(node->GetSimdBaseType()) && op1->OperIs(GT_CAST))
-    {
-        // We will sometimes get a cast around a constant value (such as for
-        // certain long constants) which would block the below containment.
-        // So we will temporarily check what the cast is from instead so we
-        // can catch those cases as well.
-
-        castOp = op1->AsCast()->CastOp();
-
-        if (varTypeIsIntegral(castOp))
-        {
-            op1 = castOp;
-        }
-        else
-        {
-            castOp = nullptr;
-        }
-    }
+    GenTree* const op1 = node->Op(1);
 
     if (op1->IsCnsIntOrI())
     {
         const ssize_t dataValue = op1->AsIntCon()->gtIconVal;
-
-        if (comp->GetEmitter()->emitIns_valid_imm_for_movi(dataValue, emitActualTypeSize(node->GetSimdBaseType())))
-        {
-            if (castOp != nullptr)
-            {
-                // We found a containable immediate under
-                // a cast, so remove the cast from the LIR.
-
-                BlockRange().Remove(node->Op(1));
-                node->Op(1) = op1;
-            }
-            return true;
-        }
+        return comp->GetEmitter()->emitIns_valid_imm_for_movi(dataValue, emitActualTypeSize(node->GetSimdBaseType()));
     }
     else if (op1->IsCnsFltOrDbl())
     {
         assert(varTypeIsFloating(node->GetSimdBaseType()));
-        assert(castOp == nullptr);
-
         const double dataValue = op1->AsDblCon()->DconValue();
         return comp->GetEmitter()->emitIns_valid_imm_for_fmov(dataValue);
     }

src/tests/JIT/Regression/JitBlue/Runtime_106020/Runtime_106020.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.
+
+// Generated by Fuzzlyn v2.2 on 2024-08-05 19:14:52
+// Run on Arm64 MacOS
+// Seed: 16897731911671998240-vectort,vector64,vector128,armadvsimd,armadvsimdarm64,armaes,armarmbase,armarmbasearm64,armcrc32,armcrc32arm64,armdp,armrdm,armrdmarm64,armsha1,armsha256
+// Reduced from 67.3 KiB to 0.3 KiB in 00:00:23
+// Hits JIT assert in Debug:
+// Assertion failed '(imm < maxVal) || ((imm & signBitsMask) == signBitsMask)' in 'Program:Main(Fuzzlyn.ExecutionServer.IRuntime)' during 'Generate code' (IL size 16; hash 0xade6b36b; MinOpts)
+// 
+//     File: /Users/runner/work/1/s/src/coreclr/jit/emitarm64.cpp Line: 2676
+// 
+using System;
+using System.Numerics;
+using System.Runtime.Intrinsics;
+using Xunit;
+
+public class Runtime_106020
+{
+    [Fact]
+    public static void Method0()
+    {
+        int vr2 = 0;
+        var result = Vector128.Create<short>((short)((0 * vr2) + 2147483647));
+        Assert.Equal(result, Vector128.Create<short>(-1));
+    }
+}

src/tests/JIT/Regression/JitBlue/Runtime_106020/Runtime_106020.csproj

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