derived-definitions ( cfg -- derived )


Vocabulary
compiler.cfg.register-allocation.ssa.bases

Inputs
cfgan object


Outputs
derivedan object


Definition
USING: assocs compiler.cfg.def-use compiler.cfg.linearization
kernel math sequences ;

IN: compiler.cfg.register-allocation.ssa.bases

:: derived-definitions ( cfg -- derived )
cfg cfg>insns :> instructions
H{ } clone :> previous! instructions length 1 +
:> remaining! t :> changed!
[ changed ] [
remaining zero?
[ inconsistent-ssa-derived-pointers ] when remaining 1 -
remaining! H{ } clone :> current instructions [| insn |
previous insn derived-definition?
[ insn defs-vregs [ t swap current set-at ] each ]
when
] each current previous = not changed! current previous!
] while previous ;