  In the ferromagnetic Weyl semimetal CeAlSi both space-inversion and
time-reversal symmetries are broken. We use external pressure as an effective
tuning parameter and relate three observations to the presence of a nontrivial
topology in its ferromagnetic regime: an exceptional temperature response of
the quantum oscillations amplitude, the presence of an anomalous Hall effect
(AHE), and the existence of an unusual loop Hall effect (LHE). We find a
suppression of the AHE and the LHE with increasing pressure, while the Curie
temperature is enhanced. The magnetic structure and the electronic bands
exhibit only a negligible pressure effect suggesting the importance of the
domain wall landscape for the topological behavior in CeAlSi.
