Merge remote-tracking branch 'origin/master' into xc7mux

diff --cc techlibs/xilinx/synth_xilinx.cc
index 1320673e5c0e0f92b075666bc0057a8d55c5e08e,58dd928a0e05c3e938331f178957472d15478565..524c54d3bc50a0b9887abd0a34209341b8fd4d3b
--- 1/techlibs/xilinx/synth_xilinx.cc
--- 2/techlibs/xilinx/synth_xilinx.cc
+++ b/techlibs/xilinx/synth_xilinx.cc
@@@ -292,14 -269,12 +292,13 @@@ struct SynthXilinxPass : public Pas
                        Pass::call(design, "dffsr2dff");
                        Pass::call(design, "dff2dffe");
  
 -                      if (vpr) {
 -                              Pass::call(design, "techmap -map +/xilinx/arith_map.v -D _EXPLICIT_CARRY");
 -                      } else {
 -                              Pass::call(design, "techmap -map +/xilinx/arith_map.v");
 +                      if (!nocarry) {
 +                              if (vpr)
 +                                      Pass::call(design, "techmap -map +/xilinx/arith_map.v -D _EXPLICIT_CARRY");
 +                              else
 +                                      Pass::call(design, "techmap -map +/xilinx/arith_map.v");
                        }
  
-                       Pass::call(design, "hierarchy -check");
                        Pass::call(design, "opt -fast");
                }