Erik Eckstein 8be0ca07c2 SIL optimizer: remove unbalanced retains/releases from immortal objects ...

ARC operations don't have an effect on immortal objects, like the empty array singleton or statically allocated arrays.
Therefore we can freely remove and retain/release instructions on such objects, even if there is no paired balanced ARC operation.

This optimization can only be done with a minimum deployment target of Swift 5.1, because in that version we added immortal ref count bits.

The optimization is implemented in libswift. Additionally, the remaining logic of simplifying strong_retain and strong_release is also ported to libswift.

rdar://81482156

2021-08-23 10:23:59 +02:00

1.9 KiB

Raw Blame History

View Raw