passes/opt/opt.cc

   1 /*
   2  *  yosys -- Yosys Open SYnthesis Suite
   3  *
   4  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
   5  *
   6  *  Permission to use, copy, modify, and/or distribute this software for any
   7  *  purpose with or without fee is hereby granted, provided that the above
   8  *  copyright notice and this permission notice appear in all copies.
   9  *
  10  *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  *
  18  */
  19
  20 #include "opt_status.h"
  21 #include "kernel/register.h"
  22 #include "kernel/log.h"
  23 #include <stdlib.h>
  24 #include <stdio.h>
  25
  26 bool OPT_DID_SOMETHING;
  27
  28 struct OptPass : public Pass {
  29         OptPass() : Pass("opt", "perform simple optimizations") { }
  30         virtual void help()
  31         {
  32                 //   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
  33                 log("\n");
  34                 log("    opt [selection]\n");
  35                 log("\n");
  36                 log("This pass calls all the other opt_* passes in a useful manner. This performs\n");
  37                 log("a series of trivial optimizations and cleanups. This pass executes the other\n");
  38                 log("passes in the following order:\n");
  39                 log("\n");
  40                 log("    opt_const\n");
  41                 log("    opt_share -nomux\n");
  42                 log("\n");
  43                 log("    do\n");
  44                 log("        opt_muxtree\n");
  45                 log("        opt_reduce\n");
  46                 log("        opt_share\n");
  47                 log("        opt_rmdff\n");
  48                 log("        opt_rmunused\n");
  49                 log("        opt_const\n");
  50                 log("    while [changed design]\n");
  51                 log("\n");
  52         }
  53         virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
  54         {
  55                 log_header("Executing OPT pass (performing simple optimizations).\n");
  56                 log_push();
  57
  58                 extra_args(args, 1, design);
  59
  60                 log_header("Optimizing in-memory representation of design.\n");
  61                 design->optimize();
  62
  63                 Pass::call(design, "opt_const");
  64                 Pass::call(design, "opt_share -nomux");
  65                 while (1) {
  66                         OPT_DID_SOMETHING = false;
  67                         Pass::call(design, "opt_muxtree");
  68                         Pass::call(design, "opt_reduce");
  69                         Pass::call(design, "opt_share");
  70                         Pass::call(design, "opt_rmdff");
  71                         Pass::call(design, "opt_rmunused");
  72                         Pass::call(design, "opt_const");
  73                         if (OPT_DID_SOMETHING == false)
  74                                 break;
  75                         log_header("Rerunning OPT passes. (Maybe there is more to do..)\n");
  76                 }
  77
  78                 log_header("Optimizing in-memory representation of design.\n");
  79                 design->optimize();
  80
  81                 log_header("Finished OPT passes. (There is nothing left to do.)\n");
  82                 log_pop();
  83         }
  84 } OptPass;
  85