Add doc

diff --git a/passes/opt/muxpack.cc b/passes/opt/muxpack.cc
index ae4f7ba9cbd78332cedd9b55d808f4e9cf394419..c8b226c78e916a8ecc76582437facc570069de5e 100644 (file)
--- a/passes/opt/muxpack.cc
+++ b/passes/opt/muxpack.cc
@@ -304,9 +304,9 @@ struct MuxpackPass : public Pass {
                log("constructs) and $mux cells (e.g. those created by if-else constructs) into\n");
                log("$pmux cells.\n");
                log("\n");
-               log("This optimisation is conservative --- it will only pack $mux or $pmux cells with\n");
-               log("other such cells if it can be certain that the select lines are mutually\n");
-               log("exclusive.\n");
+               log("This optimisation is conservative --- it will only pack $mux or $pmux cells\n");
+               log("whose select lines are driven by '$eq' cells with other such cells if it can be\n");
+               log("certain that their select inputs are mutually exclusive.\n");
                log("\n");
        }
        void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE