Merge remote-tracking branch 'origin/master' into xaig_dff

diff --cc techlibs/xilinx/cells_sim.v
Simple merge

diff --cc techlibs/xilinx/synth_xilinx.cc
index af9f21756fd6f6122b939855d9c58fc3ab44464c,b0c4795eec655355f2153868eae63e75d04c4a01..e2a625f9b0b4b22332dd844c9bc712995155004b
--- 1/techlibs/xilinx/synth_xilinx.cc
--- 2/techlibs/xilinx/synth_xilinx.cc
+++ b/techlibs/xilinx/synth_xilinx.cc
@@@ -107,11 -107,8 +107,11 @@@ struct SynthXilinxPass : public ScriptP
                log("    -flatten\n");
                log("        flatten design before synthesis\n");
                log("\n");
 +              log("    -dff\n");
 +              log("        run 'abc9' with -dff option\n");
 +              log("\n");
                log("    -retime\n");
-               log("        run 'abc' with -dff option\n");
+               log("        run 'abc' with '-dff -D 1' options\n");
                log("\n");
                log("    -abc9\n");
                log("        use new ABC9 flow (EXPERIMENTAL)\n");