Address review comments

Author: msimacek

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/cext/PythonCextUnicodeBuiltins.java

@@ -774,11 +774,10 @@ abstract static class PyUnicodeSplit extends PythonQuaternaryBuiltinNode {
         @Specialization
         Object split(VirtualFrame frame, Object module, Object string, Object sep, Object maxsplit,
                         @Cached StringBuiltins.SplitNode splitNode,
-                        @Cached ToNewRefNode toSulongNode,
                         @Cached TransformExceptionToNativeNode transformExceptionToNativeNode,
                         @Cached GetNativeNullNode getNativeNullNode) {
             try {
-                return toSulongNode.execute(splitNode.execute(frame, string, sep, maxsplit));
+                return splitNode.execute(frame, string, sep, maxsplit);
             } catch (PException e) {
                 transformExceptionToNativeNode.execute(frame, e);
                 return getNativeNullNode.execute(module);

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/str/StringBuiltins.java

@@ -2506,12 +2506,7 @@ public String doString(VirtualFrame frame, Object self, PSlice slice,
                         @Cached CoerceToIntSlice sliceCast,
                         @Cached ComputeIndices compute,
                         @Cached StrGetItemNodeWithSlice getItemNodeWithSlice) {
-            String str;
-            try {
-                str = castToJavaString.execute(self);
-            } catch (CannotCastException e) {
-                throw raise(TypeError, ErrorMessages.DESCRIPTOR_REQUIRES_OBJ, __GETITEM__, "str", self);
-            }
+            String str = castToString(self, castToJavaString);
             SliceInfo info = compute.execute(frame, sliceCast.execute(slice), str.length());
             return getItemNodeWithSlice.execute(str, info);
         }
@@ -2520,12 +2515,7 @@ public String doString(VirtualFrame frame, Object self, PSlice slice,
         public String doString(VirtualFrame frame, Object self, Object idx,
                         @Cached CastToJavaStringNode castToJavaString,
                         @Cached PyNumberAsSizeNode asSizeNode) {
-            String str;
-            try {
-                str = castToJavaString.execute(self);
-            } catch (CannotCastException e) {
-                throw raise(TypeError, ErrorMessages.DESCRIPTOR_REQUIRES_OBJ, __GETITEM__, "str", self);
-            }
+            String str = castToString(self, castToJavaString);
             int index = asSizeNode.executeExact(frame, idx);
             if (index < 0) {
                 index += str.length();
@@ -2541,6 +2531,14 @@ private static String charAtToString(String primary, int index) {
             char character = primary.charAt(index);
             return String.valueOf(character);
         }
+
+        private String castToString(Object self, CastToJavaStringNode castToJavaString) {
+            try {
+                return castToJavaString.execute(self);
+            } catch (CannotCastException e) {
+                throw raise(TypeError, ErrorMessages.DESCRIPTOR_REQUIRES_OBJ, __GETITEM__, "str", self);
+            }
+        }
     }
 
     @Builtin(name = __ITER__, minNumOfPositionalArgs = 1)