P4　provides　operators　with　the　ability　to　program　the　packet　processing　pipeline　of　the　data　plane　device.　The　match-action　table　(MAT)　is　a　basic　component　of　the　P4　pipeline　that　matches　the　packet　and　performs　an　action　on　the　matched　packet.　However,　different　MATs　may　execute　duplicate　match　operations　that　decreases　the　performance　of　the　P4　pipeline.　To　this　end,　we　present　MATReduce,　a　framework　that　optimizes　the　P4　pipeline　by　reducing　duplicate　match　operations　between　MATs.　MATReduce　is　composed　of　two　key　components,　the　preprocessor　and　the　runtime　manager.　By　introducing　the　compound　MAT　and　rewriting　the　P4　control　flow,　the　preprocessor　merges　duplicate　match　operations　of　the　P4　pipeline　while　maintaining　the　program　semantics.　At　runtime,　the　runtime　manager　converts　user　rules　to　actual　rules　for　maintaining　the　policy　consistency.　Our　preliminary　experimental　results　show　that　MATReduce　provides　significant　performance　improvement,　including　a　23.90%　throughput　increase　and　a　34.37%　delay　decrease　on　the　software　target,　and　a　45.19%　delay　decrease　on　the　hardware　target.　©　2018　IEEE.