fold-only-branch ( #branch -- node/nodes )

Vocabulary

compiler.tree.cleanup

Inputs

#branch

a #branch

Outputs

node/nodes

a node or a sequence of nodes

Word description

If only one branch is live we don't need to branch at all; just drop the condition value.

Definition

USING: accessors combinators compiler.tree
compiler.tree.propagation.branches kernel sequences ;

IN: compiler.tree.cleanup

: fold-only-branch ( #branch -- node/nodes )
    dup live-children sift dup length {
        { 0 [ drop in-d>> <#drop> ] }
        { 1 [ first swap in-d>> <#drop> prefix ] }
        [ 2drop ]
    } case ;