Use more specific return type

Author: JukkaL

mypyc/primitives/str_ops.py

@@ -16,6 +16,7 @@
     list_rprimitive,
     object_rprimitive,
     pointer_rprimitive,
+    short_int_rprimitive,
     str_rprimitive,
     tuple_rprimitive,
 )
@@ -536,7 +537,7 @@
 str_get_item_unsafe_as_int_op = custom_primitive_op(
     name="str_get_item_unsafe_as_int",
     arg_types=[str_rprimitive, int64_rprimitive],
-    return_type=int_rprimitive,
+    return_type=short_int_rprimitive,
     c_function_name="CPyStr_GetItemUnsafeAsInt",
     error_kind=ERR_NEVER,
     dependencies=[STR_EXTRA_OPS],

mypyc/test-data/irbuild-str.test

@@ -525,7 +525,7 @@ def ord_str_index(s, i):
     r5 :: c_ptr
     r6, r7 :: i64
     r8, r9 :: bool
-    r10 :: int
+    r10 :: short_int
 L0:
     r0 = i & 1
     r1 = r0 == 0
@@ -554,7 +554,7 @@ def ord_str_index_i64(s, i):
     s :: str
     i, r0 :: i64
     r1, r2 :: bool
-    r3 :: int
+    r3 :: short_int
 L0:
     r0 = CPyStr_AdjustIndex(s, i)
     r1 = CPyStr_RangeCheck(s, r0)