yosys/passes/silimate/negopt.cc

120 lines
3.3 KiB
C++

/*
* Copyright (C) 2025 Silimate, Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*/
//
// Authored by Abhinav Tondapu of Silimate, Inc.
//
#include "kernel/yosys.h"
#include "kernel/sigtools.h"
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
bool did_something;
#include "passes/silimate/peepopt_negopt.h"
struct NegoptPass : public Pass {
NegoptPass() : Pass("negopt", "optimize negation patterns in arithmetic") { }
void help() override
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" negopt [options] [selection]\n");
log("\n");
log("This pass optimizes negation patterns in arithmetic expressions.\n");
log("\n");
log(" -pre\n");
log(" Run pre-optimization transformations:\n" );
log(" - manual2sub: a + ~b + 1 => a - b\n" );
log(" - sub2neg: a - b => a + (-b)\n" );
log(" - negexpand: -(a + b) => (-a) + (-b)\n");
log(" - negneg: -(-a) => a\n" );
log(" - negmux: -(s?a:b) => s?(-a):(-b)\n");
log("\n");
log(" -post\n");
log(" Run post-optimization transformations:\n" );
log(" - negrebuild: (-a)+(-b) => -(a + b)\n");
log(" - muxneg: s?(-a):(-b) => -(s?a:b)\n");
log(" - neg2sub: a + (-b) => a - b\n" );
log("\n");
log("When called without options, both -pre and -post are executed.\n");
log("\n");
}
void execute(std::vector<std::string> args, RTLIL::Design *design) override
{
bool run_pre = false;
bool run_post = false;
log_header(design, "Executing NEGOPT pass (optimize negation patterns).\n");
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++) {
if (args[argidx] == "-pre") {
run_pre = true;
continue;
}
if (args[argidx] == "-post") {
run_post = true;
continue;
}
break;
}
extra_args(args, argidx, design);
if (!run_pre && !run_post) {
run_pre = true;
run_post = true;
}
for (auto module : design->selected_modules()) {
if (run_pre) {
did_something = true;
while (did_something) {
did_something = false;
peepopt_pm pm(module);
pm.setup(module->selected_cells());
pm.run_manual2sub(); // Reduce manual 2's complement to subtraction first
pm.run_sub2neg();
pm.run_negexpand();
pm.run_negneg();
pm.run_negmux();
}
}
if (run_post) {
did_something = true;
while (did_something) {
did_something = false;
peepopt_pm pm(module);
pm.setup(module->selected_cells());
pm.run_negrebuild();
pm.run_muxneg();
pm.run_neg2sub();
}
}
}
}
} NegoptPass;
PRIVATE_NAMESPACE_END