Fix missing side-effects handling in gtFoldTypeCompare (#121875)

Fixes #121874

Author: EgorBo

src/coreclr/jit/gentree.cpp

@@ -14266,18 +14266,6 @@ GenTree* Compiler::gtFoldTypeCompare(GenTree* tree)
         return tree;
     }
 
-    // Check if an object of this type can even exist
-    if (info.compCompHnd->getExactClasses(clsHnd, 0, nullptr) == 0)
-    {
-        JITDUMP("Runtime reported %p (%s) is never allocated\n", dspPtr(clsHnd), eeGetClassName(clsHnd));
-
-        const bool operatorIsEQ  = (oper == GT_EQ);
-        const int  compareResult = operatorIsEQ ? 0 : 1;
-        JITDUMP("Runtime reports comparison is known at jit time: %u\n", compareResult);
-        GenTree* result = gtNewIconNode(compareResult);
-        return result;
-    }
-
     // We're good to go.
     JITDUMP("Optimizing compare of obj.GetType()"
             " and type-from-handle to compare method table pointer\n");
@@ -14298,6 +14286,20 @@ GenTree* Compiler::gtFoldTypeCompare(GenTree* tree)
         objOp = opOther->AsCall()->gtArgs.GetThisArg()->GetNode();
     }
 
+    // Check if an object of this type can even exist
+    if (info.compCompHnd->getExactClasses(clsHnd, 0, nullptr) == 0)
+    {
+        JITDUMP("Runtime reported %p (%s) is never allocated\n", dspPtr(clsHnd), eeGetClassName(clsHnd));
+
+        const bool operatorIsEQ  = (oper == GT_EQ);
+        const int  compareResult = operatorIsEQ ? 0 : 1;
+        JITDUMP("Runtime reports comparison is known at jit time: %u\n", compareResult);
+
+        GenTree* result      = gtNewIconNode(compareResult);
+        GenTree* sideEffects = fgAddrCouldBeNull(objOp) ? gtNewNullCheck(objOp) : objOp;
+        return gtWrapWithSideEffects(result, sideEffects, GTF_ALL_EFFECT);
+    }
+
     bool                 isExact   = false;
     bool                 isNonNull = false;
     CORINFO_CLASS_HANDLE objCls    = gtGetClassHandle(objOp, &isExact, &isNonNull);