: emit-fixnum-shift-fast ( block #call -- block' )
node-input-infos second interval>> {
{ [ dup 0 [a,inf] interval-subset? ] [ drop emit-fixnum-left-shift ] }
- { [ dup 0 [-inf,a] interval-subset? ] [ drop emit-fixnum-right-shift ] }
+ { [ dup 0 [-inf,b] interval-subset? ] [ drop emit-fixnum-right-shift ] }
[ drop emit-fixnum-shift-general ]
} cond ;