PERF: cdef UTC (#34043)

Author: jbrockmendel

pandas/_libs/tslibs/c_timestamp.pyx

@@ -37,8 +37,9 @@ from pandas._libs.tslibs.np_datetime import OutOfBoundsDatetime
 from pandas._libs.tslibs.np_datetime cimport (
     reverse_ops, cmp_scalar)
 from pandas._libs.tslibs.timezones cimport (
-    get_timezone, is_utc, tz_compare)
-from pandas._libs.tslibs.timezones import UTC
+    get_timezone, is_utc, tz_compare,
+    utc_pytz as UTC,
+)
 from pandas._libs.tslibs.tzconversion cimport tz_convert_single
 from pandas._libs.tslibs.offsets cimport is_tick_object
 

pandas/_libs/tslibs/conversion.pyx

@@ -28,8 +28,9 @@ from pandas._libs.tslibs.util cimport (
 from pandas._libs.tslibs.timedeltas cimport cast_from_unit
 from pandas._libs.tslibs.timezones cimport (
     is_utc, is_tzlocal, is_fixed_offset, get_utcoffset, get_dst_info,
-    get_timezone, maybe_get_tz, tz_compare)
-from pandas._libs.tslibs.timezones import UTC
+    get_timezone, maybe_get_tz, tz_compare,
+    utc_pytz as UTC,
+)
 from pandas._libs.tslibs.parsing import parse_datetime_string
 
 from pandas._libs.tslibs.nattype import nat_strings

pandas/_libs/tslibs/offsets.pyx

@@ -30,7 +30,7 @@ from pandas._libs.tslibs.conversion cimport (
 from pandas._libs.tslibs.nattype cimport NPY_NAT
 from pandas._libs.tslibs.np_datetime cimport (
     npy_datetimestruct, dtstruct_to_dt64, dt64_to_dtstruct)
-from pandas._libs.tslibs.timezones import UTC
+from pandas._libs.tslibs.timezones cimport utc_pytz as UTC
 from pandas._libs.tslibs.tzconversion cimport tz_convert_single
 from pandas._libs.tslibs.c_timestamp cimport _Timestamp
 

pandas/_libs/tslibs/timestamps.pyx

@@ -25,8 +25,8 @@ from pandas._libs.tslibs.np_datetime cimport (
 from pandas._libs.tslibs.offsets cimport to_offset
 from pandas._libs.tslibs.timedeltas import Timedelta
 from pandas._libs.tslibs.timezones cimport (
-    is_utc, maybe_get_tz, treat_tz_as_pytz)
-from pandas._libs.tslibs.timezones import UTC
+    is_utc, maybe_get_tz, treat_tz_as_pytz, utc_pytz as UTC
+)
 from pandas._libs.tslibs.tzconversion import (
     tz_localize_to_utc, tz_convert_single)
 

pandas/_libs/tslibs/timezones.pxd

@@ -1,3 +1,7 @@
+from cpython.datetime cimport tzinfo
+
+cdef tzinfo utc_pytz
+
 cpdef bint is_utc(object tz)
 cdef bint is_tzlocal(object tz)
 
@@ -8,7 +12,7 @@ cpdef bint tz_compare(object start, object end)
 cpdef object get_timezone(object tz)
 cpdef object maybe_get_tz(object tz)
 
-cdef get_utcoffset(tzinfo, obj)
+cdef get_utcoffset(tzinfo tz, obj)
 cdef bint is_fixed_offset(object tz)
 
 cdef object get_dst_info(object tz)

pandas/_libs/tslibs/timezones.pyx

@@ -1,3 +1,4 @@
+from cpython.datetime cimport tzinfo
 from datetime import timezone
 
 # dateutil compat
@@ -24,12 +25,13 @@ cnp.import_array()
 from pandas._libs.tslibs.util cimport is_integer_object, get_nat
 
 cdef int64_t NPY_NAT = get_nat()
-cdef object utc_stdlib = timezone.utc
+cdef tzinfo utc_stdlib = timezone.utc
+cdef tzinfo utc_pytz = UTC
 
 # ----------------------------------------------------------------------
 
 cpdef inline bint is_utc(object tz):
-    return tz is UTC or tz is utc_stdlib or isinstance(tz, _dateutil_tzutc)
+    return tz is utc_pytz or tz is utc_stdlib or isinstance(tz, _dateutil_tzutc)
 
 
 cdef inline bint is_tzlocal(object tz):
@@ -152,11 +154,11 @@ cdef inline object tz_cache_key(object tz):
 # UTC Offsets
 
 
-cdef get_utcoffset(tzinfo, obj):
+cdef get_utcoffset(tzinfo tz, obj):
     try:
-        return tzinfo._utcoffset
+        return tz._utcoffset
     except AttributeError:
-        return tzinfo.utcoffset(obj)
+        return tz.utcoffset(obj)
 
 
 cdef inline bint is_fixed_offset(object tz):