rewrite literal DEF integer coercion to constants:

- append U-suffix only on coercion when the target type is unsigned
- append L/LL-suffix when value looks too large for a smaller constant value type

Cython/Compiler/ExprNodes.py

@@ -1148,9 +1148,15 @@ class IntNode(ConstNode):
                 return FloatNode(self.pos, value=self.value, type=dst_type,
                                  constant_result=not_a_constant)
         if dst_type.is_numeric and not dst_type.is_complex:
+            unsigned = self.unsigned
+            if not unsigned and dst_type.is_int and not dst_type.signed:
+                # mark positive literals as 'U' when coercing them to unsigned integer types
+                # to extend their potential value range in the C code
+                if self.has_constant_result() and self.constant_result > 0:
+                    unsigned = 'U'
             node = IntNode(self.pos, value=self.value, constant_result=self.constant_result,
-                           type = dst_type, is_c_literal = True,
-                           unsigned=self.unsigned, longness=self.longness)
+                           type=dst_type, is_c_literal=True,
+                           unsigned=unsigned, longness=self.longness)
             return node
         elif dst_type.is_pyobject:
             node = IntNode(self.pos, value=self.value, constant_result=self.constant_result,

Cython/Compiler/Parsing.py

@@ -763,7 +763,7 @@ def wrap_compile_time_constant(pos, value):
         return ExprNodes.BoolNode(pos, value=value)
     elif isinstance(value, int):
         return ExprNodes.IntNode(
-            pos, value=rep, constant_result=value, unsigned='U' if value > 0 else '')
+            pos, value=rep, constant_result=value, longness=Utils.longness_of(value))
     elif isinstance(value, float):
         return ExprNodes.FloatNode(pos, value=rep, constant_result=value)
     elif isinstance(value, _unicode):
@@ -781,8 +781,7 @@ def wrap_compile_time_constant(pos, value):
             return None
     elif not _IS_PY3 and isinstance(value, long):
         return ExprNodes.IntNode(
-            pos, value=rep.rstrip('L'), longness="L", constant_result=value,
-            unsigned='U' if value > 0 else '')
+            pos, value=rep.rstrip('L'), longness=Utils.longness_of(value), constant_result=value)
     error(pos, "Invalid type for compile-time constant: %r (type %s)"
                % (value, value.__class__.__name__))
     return None

Cython/Utils.py

@@ -319,6 +319,16 @@ def long_literal(value):
     return not -2**31 <= value < 2**31
 
 
+def longness_of(value):
+    if isinstance(value, basestring):
+        value = str_to_number(value)
+    if -2**15 <= value < 2**15:
+        return ''
+    if -2**31 <= value < 2**31:
+        return 'L'
+    return 'LL'
+
+
 @cached_function
 def get_cython_cache_dir():
     """get the cython cache dir

tests/run/ct_DEF.pyx

@@ -94,15 +94,18 @@ def l():
 
 def large_nums():
     """
-    >>> l32, l64 = large_nums()
-    >>> print_large_number(l32)
+    >>> ul32, ul64, l64 = large_nums()
+    >>> print_large_number(ul32)
     4294967295
-    >>> print_large_number(l64)
+    >>> print_large_number(ul64)
     18446744073709551615
+    >>> print_large_number(l64)
+    4294967295
     """
-    cdef unsigned long l32 = LARGE_NUM32
-    cdef unsigned long long l64 = LARGE_NUM64
-    return l32, l64
+    cdef unsigned long ul32 = LARGE_NUM32
+    cdef unsigned long long ul64 = LARGE_NUM64
+    cdef long long l64 = LARGE_NUM32
+    return ul32, ul64, l64
 
 def f():
     """