factor/basis/compiler/cfg/useless-conditionals/useless-conditionals.factor

34 lines
1.1 KiB
Factor

! Copyright (C) 2008, 2010 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
USING: kernel accessors sequences math combinators
combinators.short-circuit vectors compiler.cfg
compiler.cfg.instructions compiler.cfg.rpo
compiler.cfg.utilities ;
IN: compiler.cfg.useless-conditionals
: delete-conditional? ( bb -- ? )
{
[
instructions>> last {
[ ##compare-branch? ]
[ ##compare-imm-branch? ]
[ ##compare-integer-branch? ]
[ ##compare-integer-imm-branch? ]
[ ##compare-float-ordered-branch? ]
[ ##compare-float-unordered-branch? ]
} 1||
]
[ successors>> first2 [ skip-empty-blocks ] bi@ eq? ]
} 1&& ;
: delete-conditional ( bb -- )
[ first skip-empty-blocks 1vector ] change-successors
instructions>> [ pop* ] [ [ \ ##branch new-insn ] dip push ] bi ;
: delete-useless-conditionals ( cfg -- cfg' )
dup [
dup delete-conditional? [ delete-conditional ] [ drop ] if
] each-basic-block
cfg-changed predecessors-changed ;