remove-unused-spill-phis ( cfg -- )

Vocabulary

compiler.cfg.register-allocation.chordal.spilling

Inputs

cfg

an object

Outputs

None

Definition

USING: accessors assocs compiler.cfg.instructions
compiler.cfg.linearization
compiler.cfg.register-allocation.chordal.spilling.next-use
compiler.cfg.rpo compiler.utilities kernel sequences ;

IN: compiler.cfg.register-allocation.chordal.spilling

:: remove-unused-spill-phis ( cfg -- )
    cfg cfg>insns :> instructions instructions [ ##phi? ] filter
    :> phis H{ } clone :> needed instructions [ ##phi? ] reject
    [ spill-insn-uses [ needed conjoin ] each ] each
    t :> changed!
    [ changed ] [
        needed assoc-size :> before phis [| phi |
            phi dst>> needed key?
            [ phi inputs>> values [ needed conjoin ] each ] when
        ] each needed assoc-size before = not changed!
    ] while cfg [| bb |
        bb [
            [| insn |
                insn ##phi?
                [ insn dst>> needed key? not ] [ f ] if dup
                [ "dead-phis-removed" spill-stat ] when
            ] reject
        ] change-instructions drop
    ] each-basic-block ;