Changes in a ST: Illustration
17/43
none
(
i
)
(
i
)
dead
live
live
a
b
c
next use
status
var
…
…
…
…
…
ST:
a
is dead because
a
:=
b
+
c
kills
any
previous
definition of
a
b
,
c
are alive and used in (
i
); this
information reflects the situation
earlier
in the block
(
i
)
a
:=
b
+
c
backward