diff --git a/src/coreclr/jit/valuenum.cpp b/src/coreclr/jit/valuenum.cpp
index 7d836353baea18..30a66726279ca2 100644
--- a/src/coreclr/jit/valuenum.cpp
+++ b/src/coreclr/jit/valuenum.cpp
@@ -2610,6 +2610,37 @@ ValueNum ValueNumStore::VNForFunc(var_types typ, VNFunc func, ValueNum arg0VN)
             {
                 *resultVN = VNForIntCon(knownSize);
             }
+
+            // Case 4: ARR_LENGTH(new T[(long)size]) -> size
+            VNFuncApp newArrFuncApp;
+            if (GetVNFunc(arg0VN, &newArrFuncApp) && (newArrFuncApp.m_func == VNF_JitNewArr))
+            {
+                ValueNum  actualSizeVN     = newArrFuncApp.m_args[1];
+                var_types actualSizeVNType = TypeOfVN(actualSizeVN);
+
+                // JitNewArr's size argument (args[1]) is typically upcasted to TYP_LONG via VNF_Cast.
+                if (actualSizeVNType == TYP_LONG)
+                {
+                    VNFuncApp castFuncApp;
+                    if (GetVNFunc(actualSizeVN, &castFuncApp) && (castFuncApp.m_func == VNF_Cast))
+                    {
+                        var_types castToType;
+                        bool      srcIsUnsigned;
+                        GetCastOperFromVN(castFuncApp.m_args[1], &castToType, &srcIsUnsigned);
+
+                        // Make sure we have exactly (TYP_LONG)myInt32 cast:
+                        if (!srcIsUnsigned && (castToType == TYP_LONG) && TypeOfVN(castFuncApp.m_args[0]) == TYP_INT)
+                        {
+                            // If that is the case, return the original size argument
+                            *resultVN = castFuncApp.m_args[0];
+                        }
+                    }
+                }
+                else if (actualSizeVNType == TYP_INT)
+                {
+                    *resultVN = actualSizeVN;
+                }
+            }
         }
 
         // Try to perform constant-folding.