yosys/passes/silimate/opt_shift.cc

110 lines
3.6 KiB
C++

/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2012 Claire Xenia Wolf <claire@yosyshq.com>
* Akash Levy <akash@silimate.com>
*
* 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.
*
*/
#include "kernel/yosys.h"
#include "kernel/sigtools.h"
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
bool did_something;
#include "passes/silimate/peepopt_shift.h"
struct OptShiftPass : public Pass {
OptShiftPass() : Pass("opt_shift", "shift optimizations: combine and expand") { }
void help() override
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" opt_shift [options] [selection]\n");
log("\n");
log("This pass performs shift optimizations.\n");
log("\n");
log(" -combine\n");
log(" Combine nested shift operations (works with all\n");
log(" combinations of $shl/$sshl and $shr/$sshr):\n");
log(" (a <</<< b) <</<< c ===> a <</<< (b + c)\n");
log(" (a >>>/>> b) >>>/>> c ===> a >>>/>> (b + c)\n");
log(" (a <</<< b) >>>/>> c ===> a <</<< (b - c)\n");
log(" (a >>>/>> b) <</<< c ===> a >>>/>> (b - c)\n");
log(" Result uses the inner shift's type.\n");
log("\n");
log(" -expand\n");
log(" Expand shifts across binary operations:\n");
log(" (a OP b) << c ===> (a << c) OP (b << c)\n");
log(" (a OP b) >> c ===> (a >> c) OP (b >> c)\n");
log(" where OP in {$and, $or, $xor, $add, $sub}\n");
log("\n");
log(" -max_iters n\n");
log(" max number of pass iterations to run.\n");
log("\n");
log("If neither -combine nor -expand is given, both are run.\n");
log("\n");
}
void execute(std::vector<std::string> args, RTLIL::Design *design) override
{
log_header(design, "Executing OPT_SHIFT pass (shift optimizations).\n");
bool run_combine = false;
bool run_expand = false;
int max_iters = 10000;
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++) {
if (args[argidx] == "-combine") {
run_combine = true;
continue;
}
if (args[argidx] == "-expand") {
run_expand = true;
continue;
}
if (args[argidx] == "-max_iters" && argidx + 1 < args.size()) {
max_iters = std::stoi(args[++argidx]);
continue;
}
break;
}
extra_args(args, argidx, design);
if (!run_combine && !run_expand) {
run_combine = true;
run_expand = true;
}
for (auto module : design->selected_modules())
{
did_something = true;
for (int i = 0; did_something && i < max_iters; i++)
{
did_something = false;
peepopt_pm pm(module);
pm.setup(module->selected_cells());
if (run_combine)
pm.run_combine_shifts();
if (run_expand)
pm.run_expand_shifts();
}
}
}
} OptShiftPass;
PRIVATE_NAMESPACE_END