Handle a missing case in zero-extend peephole

src/coreclr/jit/emitxarch.cpp

@@ -296,6 +296,13 @@ bool emitter::AreUpper32BitsZero(regNumber reg)
                 return false;
             }
 
+#ifdef TARGET_AMD64
+            if (id->idIns() == INS_movsxd)
+            {
+                return false;
+            }
+#endif
+
             // movzx always zeroes the upper 32 bits.
             if (id->idIns() == INS_movzx)
             {

src/tests/JIT/Regression/JitBlue/Runtime_55129/Runtime_55129.cs

@@ -0,0 +1,101 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Runtime.CompilerServices;
+
+public class Runtime_55129
+{
+    public static int Main()
+    {
+        int result = 100;
+        if (!Runtime_55129_1.Run())
+            result |= 1;
+        if (!Runtime_55129_2.Run())
+            result |= 2;
+        return result;
+    }
+}
+
+// These tests failed because of a missing zero extension because a peephole
+// did not handle that 'movsxd' would sign extend.
+public class Runtime_55129_1
+{
+    static I s_i = new C();
+    static short s_7;
+    static sbyte[][] s_10 = new sbyte[][]{new sbyte[]{-1}};
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool Run()
+    {
+        var vr59 = (uint)M6(s_10[0][0]);
+        return (long)vr59 == uint.MaxValue;
+    }
+
+    static ulong M6(sbyte arg0)
+    {
+        return (ulong)arg0;
+        ref short var1 = ref s_7;
+        s_i.Foo(var1);
+    }
+}
+
+interface I
+{
+    void Foo<T>(T val);
+}
+
+class C : I
+{
+    public void Foo<T>(T val) { }
+}
+
+struct S0
+{
+    public long F5;
+    public S0(int f0, byte f1, ulong f2, byte f3, uint f4, long f5, int f6, int f7) : this()
+    {
+    }
+}
+
+class C0
+{
+    public long F0;
+}
+
+class C1
+{
+    public ulong F1;
+}
+
+public class Runtime_55129_2
+{
+    static int[] s_2 = new int[] { -1 };
+    static C0 s_4 = new C0();
+    static S0 s_5;
+    static C1[][] s_47 = new C1[][] { new C1[] { new C1() } };
+    static bool s_result;
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    public static bool Run()
+    {
+        s_5.F5 = s_2[0];
+        C1 vr4 = s_47[0][0];
+        var vr6 = vr4.F1;
+        M6(vr6);
+        return s_result;
+    }
+
+    static void M6(ulong arg0)
+    {
+        arg0 >>= 0;
+        if (-1 < (uint)(0U | M7(ref s_4.F0, new S0[][,] { new S0[,] { { new S0(-10, 1, 0, 178, 1671790506U, -2L, 1, -2147483648) } }, new S0[,] { { new S0(1330389305, 255, 1297834355652867458UL, 0, 1777203966U, 4402572156859115751L, -1597826478, 1) } }, new S0[,] { { new S0(2147483646, 15, 18446744073709551614UL, 9, 1089668776U, 8629324174561266356L, 2124906017, -1883510008) } } }, 1, new sbyte[] { -37, -21, 0, 0, 0, 0 }, new S0[] { new S0(219671235, 22, 11763641210444381762UL, 0, 2568868236U, -7432636731544997849L, 1623417447, -479936755), new S0(-2147483647, 108, 0, 1, 4294967294U, 9223372036854775807L, 539462011, 1), new S0(1, 0, 15733997012901423027UL, 212, 4294967294U, 4663434921694141184L, -2147483647, 1196938120), new S0(1, 68, 0, 14, 653907833U, -6962955672558660864L, 1966270988, -378944819) })))
+        {
+            s_result = true;
+        }
+    }
+
+    static short M7(ref long arg0, S0[][,] arg1, ushort arg2, sbyte[] arg3, S0[] arg4)
+    {
+        long vr20 = s_5.F5;
+        return (short)vr20;
+    }
+}
+

src/tests/JIT/Regression/JitBlue/Runtime_55129/Runtime_55129.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <DebugType>None</DebugType>
+    <Optimize>True</Optimize>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildProjectName).cs" />
+  </ItemGroup>
+</Project>