What does "|" mean here: "assign IntxReq_o = |irq_reg & intx_mode;"

I saw this expression today:

assign IntxReq_o = |irq_reg & intx_mode;

noticing there is a "|" right ahead of "irq_reg". I am familiar with "|=", but never saw "=|" before.

Anyone knows?

Update:

It is reduction OR. Since irq_reg has multiple bits, the operator yields an OR result of all bits together. Apparently, I was using a much more labored way for a long time.