speed up export

Author: skirpichev

Modules/_decimal/_decimal.c

@@ -2350,7 +2350,16 @@ dec_from_long(decimal_state *state, PyTypeObject *type, PyObject *v,
         PyLong_FreeExport(&export_long);
     }
     else {
-        mpd_qset_i64(MPD(dec), export_long.value, ctx, status);
+        const int64_t value = export_long.value;
+
+        if (INT32_MIN <= value && value <= INT32_MAX) {
+            _dec_settriple(dec, value < 0 ? MPD_NEG : MPD_POS,
+                           Py_ABS(value), 0);
+            mpd_qfinalize(MPD(dec), ctx, status);
+        }
+        else {
+            mpd_qset_i64(MPD(dec), value, ctx, status);
+        }
     }
     return dec;
 }