anchor.diff:  
      module  mkReducePipes#(CombinePipe#(Tuple2#(a,a), a) combinepipe,
   			  Vector#(n, PipeOut#(a)) inpipes)
  -			 (PipeOut#(a) ifc);
  +			 (PipeOut#(a));
         Vector#(TDiv#(n,2),PipeOut#(a)) pipes0 = takeAt(0, inpipes);
         Vector#(TSub#(n,TDiv#(n,2)),PipeOut#(a)) pipes1 = takeAt(valueOf(TDiv#(n,2)), inpipes);
   
  
positive.code:    endmodule
     module  mkReducePipes#(CombinePipe#(Tuple2#(a,a), a) combinepipe,
  			  Vector#(2,PipeOut#(a)) inpipes)
  			  (PipeOut#(a) ifc);
        function a foo(Tuple2#(a,a) invec); 
  	 return combinepipe(invec);
        endfunction
  
negative.code:       );
     module  mkReducePipe#(CombinePipe#(Tuple2#(a,a), a) combinepipe,
  			 PipeOut#(Vector#(n,a)) inpipe)
  			(PipeOut#(a));
        FIFOF#(Vector#(TDiv#(n,2),a)) infifo0 <- mkFIFOF;
        FIFOF#(Vector#(TSub#(n,TDiv#(n,2)),a)) infifo1 <- mkFIFOF;
        rule splitinput;
  