A Singapore entry visa is not an immigration pass. It is a pre-entry permission for the holder of a valid visa to travel to, and seek entry, into Singapore.
The grant of an immigration pass will be determined by the ICA officers at the point of entry. The period of stay granted is shown on the visit pass endorsement given on your passport and it is not tied to the validity of your visa.
From 10 Oct 2021,
all foreign visitors arriving in Singapore via air will be notified digitally of their Visit Pass (e-Pass) through email. There will not be any endorsement on your passport. The e-Pass notification will indicate the period of stay granted
and last day of stay allowed. Please ensure that you provide a valid email address when submitting the SG Arrival Card.