Merge remote-tracking branch 'upstream/master'

11 files changed, 1314 insertions, 48 deletions

diff --git a/passes/cmds/setundef.cc b/passes/cmds/setundef.cc
index 56ef2d125..f6949c820 100644
--- a/passes/cmds/setundef.cc
+++ b/passes/cmds/setundef.cc
@@ -143,6 +143,9 @@ struct SetundefPass : public Pass {
 		log("    -init\n");
 		log("        also create/update init values for flip-flops\n");
 		log("\n");
+		log("    -params\n");
+		log("        replace undef in cell parameters\n");
+		log("\n");
 	}
 	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 	{
@@ -150,6 +153,7 @@ struct SetundefPass : public Pass {
 		bool undriven_mode = false;
 		bool expose_mode = false;
 		bool init_mode = false;
+		bool params_mode = false;
 		SetundefWorker worker;
 
 		log_header(design, "Executing SETUNDEF pass (replace undef values with defined constants).\n");
@@ -199,6 +203,10 @@ struct SetundefPass : public Pass {
 				init_mode = true;
 				continue;
 			}
+			if (args[argidx] == "-params") {
+				params_mode = true;
+				continue;
+			}
 			if (args[argidx] == "-random" && !got_value && argidx+1 < args.size()) {
 				got_value = true;
 				worker.next_bit_mode = MODE_RANDOM;
@@ -228,6 +236,18 @@ struct SetundefPass : public Pass {
 
 		for (auto module : design->selected_modules())
 		{
+			if (params_mode)
+			{
+				for (auto *cell : module->selected_cells()) {
+					for (auto &parameter : cell->parameters) {
+						for (auto &bit : parameter.second.bits) {
+							if (bit > RTLIL::State::S1)
+								bit = worker.next_bit();
+						}
+					}
+				}
+			}
+
 			if (undriven_mode)
 			{
 				if (!module->processes.empty())
diff --git a/passes/hierarchy/hierarchy.cc b/passes/hierarchy/hierarchy.cc
index 0e28dbca2..2d8edebb5 100644
--- a/passes/hierarchy/hierarchy.cc
+++ b/passes/hierarchy/hierarchy.cc
@@ -140,6 +140,23 @@ void generate(RTLIL::Design *design, const std::vector<std::string> &celltypes,
 	}
 }
 
+// Return the "basic" type for an array item.
+std::string basic_cell_type(const std::string celltype, int pos[3] = nullptr) {
+	std::string basicType = celltype;
+	if (celltype.substr(0, 7) == "$array:") {
+		int pos_idx = celltype.find_first_of(':');
+		int pos_num = celltype.find_first_of(':', pos_idx + 1);
+		int pos_type = celltype.find_first_of(':', pos_num + 1);
+		basicType = celltype.substr(pos_type + 1);
+		if (pos != nullptr) {
+			pos[0] = pos_idx;
+			pos[1] = pos_num;
+			pos[2] = pos_type;
+		}
+	}
+	return basicType;
+}
+
 bool expand_module(RTLIL::Design *design, RTLIL::Module *module, bool flag_check, bool flag_simcheck, std::vector<std::string> &libdirs)
 {
 	bool did_something = false;
@@ -178,9 +195,11 @@ bool expand_module(RTLIL::Design *design, RTLIL::Module *module, bool flag_check
 		std::vector<RTLIL::SigSpec> connections_to_add_signal;
 
 		if (cell->type.substr(0, 7) == "$array:") {
-			int pos_idx = cell->type.str().find_first_of(':');
-			int pos_num = cell->type.str().find_first_of(':', pos_idx + 1);
-			int pos_type = cell->type.str().find_first_of(':', pos_num + 1);
+			int pos[3];
+			basic_cell_type(cell->type.str(), pos);
+			int pos_idx = pos[0];
+			int pos_num = pos[1];
+			int pos_type = pos[2];
 			int idx = atoi(cell->type.str().substr(pos_idx + 1, pos_num).c_str());
 			int num = atoi(cell->type.str().substr(pos_num + 1, pos_type).c_str());
 			array_cells[cell] = std::pair<int, int>(idx, num);
@@ -439,10 +458,7 @@ void hierarchy_worker(RTLIL::Design *design, std::set<RTLIL::Module*, IdString::
 	for (auto cell : mod->cells()) {
 		std::string celltype = cell->type.str();
 		if (celltype.substr(0, 7) == "$array:") {
-			int pos_idx = celltype.find_first_of(':');
-			int pos_num = celltype.find_first_of(':', pos_idx + 1);
-			int pos_type = celltype.find_first_of(':', pos_num + 1);
-			celltype = celltype.substr(pos_type + 1);
+			celltype = basic_cell_type(celltype);
 		}
 		if (design->module(celltype))
 			hierarchy_worker(design, used, design->module(celltype), indent+4);
@@ -502,9 +518,19 @@ int find_top_mod_score(Design *design, Module *module, dict<Module*, int> &db)
 	if (db.count(module) == 0) {
 		int score = 0;
 		db[module] = 0;
-		for (auto cell : module->cells())
-			if (design->module(cell->type))
-				score = max(score, find_top_mod_score(design, design->module(cell->type), db) + 1);
+		for (auto cell : module->cells()) {
+			std::string celltype = cell->type.str();
+			// Is this an array instance
+			if (celltype.substr(0, 7) == "$array:") {
+				celltype = basic_cell_type(celltype);
+			}
+			// Is this cell a module instance?
+			auto instModule = design->module(celltype);
+			// If there is no instance for this, issue a warning.
+			if (instModule != nullptr) {
+				score = max(score, find_top_mod_score(design, instModule, db) + 1);
+			}
+		}
 		db[module] = score;
 	}
 	return db.at(module);
diff --git a/passes/opt/opt_rmdff.cc b/passes/opt/opt_rmdff.cc
index 5880254c1..e8570f0eb 100644
--- a/passes/opt/opt_rmdff.cc
+++ b/passes/opt/opt_rmdff.cc
@@ -174,8 +174,6 @@ bool handle_dffsr(RTLIL::Module *mod, RTLIL::Cell *cell)
 			cell->unsetParam("\\CLR_POLARITY");
 			cell->unsetPort("\\SET");
 			cell->unsetPort("\\CLR");
-
-			return true;
 		}
 		else
 		{
@@ -186,11 +184,12 @@ bool handle_dffsr(RTLIL::Module *mod, RTLIL::Cell *cell)
 			cell->unsetParam("\\CLR_POLARITY");
 			cell->unsetPort("\\SET");
 			cell->unsetPort("\\CLR");
-
-			return true;
 		}
+
+		return true;
 	}
-	else
+
+	if (!hasreset)
 	{
 		IdString new_type;
 
@@ -207,8 +206,10 @@ bool handle_dffsr(RTLIL::Module *mod, RTLIL::Cell *cell)
 		cell->unsetPort("\\S");
 		cell->unsetPort("\\R");
 
-		return did_something;
+		return true;
 	}
+
+	return did_something;
 }
 
 bool handle_dlatch(RTLIL::Module *mod, RTLIL::Cell *dlatch)
diff --git a/passes/opt/wreduce.cc b/passes/opt/wreduce.cc
index 8063b86a6..09983bc67 100644
--- a/passes/opt/wreduce.cc
+++ b/passes/opt/wreduce.cc
@@ -38,7 +38,8 @@ struct WreduceConfig
 			"$shl", "$shr", "$sshl", "$sshr", "$shift", "$shiftx",
 			"$lt", "$le", "$eq", "$ne", "$eqx", "$nex", "$ge", "$gt",
 			"$add", "$sub", "$mul", // "$div", "$mod", "$pow",
-			"$mux", "$pmux"
+			"$mux", "$pmux",
+			"$dff", "$adff"
 		});
 	}
 };
@@ -134,6 +135,78 @@ struct WreduceWorker
 		module->connect(sig_y.extract(n_kept, n_removed), sig_removed);
 	}
 
+	void run_cell_dff(Cell *cell)
+	{
+		// Reduce size of FF if inputs are just sign/zero extended or output bit is not used
+
+		SigSpec sig_d = mi.sigmap(cell->getPort("\\D"));
+		SigSpec sig_q = mi.sigmap(cell->getPort("\\Q"));
+
+		int width_before = GetSize(sig_q);
+
+		if (width_before == 0)
+			return;
+
+		bool zero_ext = sig_d[GetSize(sig_d)-1] == State::S0;
+		bool sign_ext = !zero_ext;
+
+		for (int i = GetSize(sig_q)-1; i >= 0; i--)
+		{
+			if (zero_ext && sig_d[i] == State::S0) {
+				module->connect(sig_q[i], State::S0);
+				sig_d.remove(i);
+				sig_q.remove(i);
+				continue;
+			}
+
+			if (sign_ext && i > 0 && sig_d[i] == sig_d[i-1]) {
+				module->connect(sig_q[i], sig_q[i-1]);
+				sig_d.remove(i);
+				sig_q.remove(i);
+				continue;
+			}
+
+			auto info = mi.query(sig_q[i]);
+			if (!info->is_output && GetSize(info->ports) <= 1 && !keep_bits.count(mi.sigmap(sig_q[i]))) {
+				sig_d.remove(i);
+				sig_q.remove(i);
+				zero_ext = false;
+				sign_ext = false;
+				continue;
+			}
+
+			break;
+		}
+
+		if (width_before == GetSize(sig_q))
+			return;
+
+		if (GetSize(sig_q) == 0) {
+			log("Removed cell %s.%s (%s).\n", log_id(module), log_id(cell), log_id(cell->type));
+			return;
+		}
+
+		log("Removed top %d bits (of %d) from mux cell %s.%s (%s).\n", width_before - GetSize(sig_q), width_before,
+				log_id(module), log_id(cell), log_id(cell->type));
+
+		for (auto bit : sig_d)
+			work_queue_bits.insert(bit);
+
+		for (auto bit : sig_q)
+			work_queue_bits.insert(bit);
+
+		// Narrow ARST_VALUE parameter to new size.
+		if (cell->parameters.count("\\ARST_VALUE")) {
+			Const arst_value = cell->getParam("\\ARST_VALUE");
+			arst_value.bits.resize(GetSize(sig_q));
+			cell->setParam("\\ARST_VALUE", arst_value);
+		}
+
+		cell->setPort("\\D", sig_d);
+		cell->setPort("\\Q", sig_q);
+		cell->fixup_parameters();
+	}
+
 	void run_reduce_inport(Cell *cell, char port, int max_port_size, bool &port_signed, bool &did_something)
 	{
 		port_signed = cell->getParam(stringf("\\%c_SIGNED", port)).as_bool();
@@ -176,6 +249,9 @@ struct WreduceWorker
 		if (cell->type.in("$mux", "$pmux"))
 			return run_cell_mux(cell);
 
+		if (cell->type.in("$dff", "$adff"))
+			return run_cell_dff(cell);
+
 		SigSpec sig = mi.sigmap(cell->getPort("\\Y"));
 
 		if (sig.has_const())
diff --git a/passes/pmgen/.gitignore b/passes/pmgen/.gitignore
new file mode 100644
index 000000000..c9263057e
--- /dev/null
+++ b/passes/pmgen/.gitignore
@@ -0,0 +1 @@
+/ice40_dsp_pm.h
diff --git a/passes/pmgen/Makefile.inc b/passes/pmgen/Makefile.inc
new file mode 100644
index 000000000..33baaca30
--- /dev/null
+++ b/passes/pmgen/Makefile.inc
@@ -0,0 +1,8 @@
+OBJS += passes/pmgen/ice40_dsp.o
+
+passes/pmgen/ice40_dsp.o: passes/pmgen/ice40_dsp_pm.h
+EXTRA_OBJS += passes/pmgen/ice40_dsp_pm.h
+.SECONDARY: passes/pmgen/ice40_dsp_pm.h
+
+passes/pmgen/ice40_dsp_pm.h: passes/pmgen/ice40_dsp.pmg passes/pmgen/pmgen.py
+	$(P) cd passes/pmgen && python3 pmgen.py ice40_dsp
diff --git a/passes/pmgen/README.md b/passes/pmgen/README.md
new file mode 100644
index 000000000..a1007dc62
--- /dev/null
+++ b/passes/pmgen/README.md
@@ -0,0 +1,224 @@
+Pattern Matcher Generator
+=========================
+
+The program `pmgen.py` reads a `.pmg` (Pattern Matcher Generator) file and
+writes a header-only C++ library that implements that pattern matcher.
+
+The "patterns" in this context are subgraphs in a Yosys RTLIL netlist.
+
+The algorithm used in the generated pattern matcher is a simple recursive
+search with backtracking. It is left to the author of the `.pmg` file to
+determine an efficient cell order for the search that allows for maximum
+use of indices and early backtracking.
+
+
+API of Generated Matcher
+========================
+
+When `pmgen.py` reads a `foobar.pmg` file, it writes `foobar_pm.h` containing
+a class `foobar_pm`. That class is instanciated with an RTLIL module and a
+list of cells from that module:
+
+    foobar_pm pm(module, module->selected_cells());
+
+The caller must make sure that none of the cells in the 2nd argument are
+deleted for as long as the patter matcher instance is used.
+
+At any time it is possible to disable cells, preventing them from showing
+up in any future matches:
+
+    pm.blacklist(some_cell);
+
+The `.run(callback_function)` method searches for all matches and calls the
+callback function for each found match:
+
+    pm.run([&](){
+        log("found matching 'foo' cell: %s\n", log_id(pm.st.foo));
+        log("          with 'bar' cell: %s\n", log_id(pm.st.bar));
+    });
+
+The `.pmg` file declares matcher state variables that are accessible via the
+`.st.<state_name>` members. (The `.st` member is of type `foobar_pm::state_t`.)
+
+Similarly the `.pmg` file declares user data variables that become members of
+`.ud`, a struct of type `foobar_pm::udata_t`.
+
+
+The .pmg File Format
+====================
+
+The `.pmg` file format is a simple line-based file format. For the most part
+lines consist of whitespace-separated tokens.
+
+Lines in `.pmg` files starting with `//` are comments.
+
+Declaring state variables
+-------------------------
+
+One or more state variables can be declared using the `state` statement,
+followed by a C++ type in angle brackets, followed by a whitespace separated
+list of variable names. For example:
+
+    state <bool> flag1 flag2 happy big
+    state <SigSpec> sigA sigB sigY
+
+State variables are automatically managed by the generated backtracking algorithm
+and saved and restored as needed.
+
+They are automatically initialized to the default constructed value of their type
+when `.run(callback_function)` is called.
+
+Declaring udata variables
+-------------------------
+
+Udata (user-data) variables can be used for example to configure the matcher or
+the callback function used to perform actions on found matches.
+
+There is no automatic management of udata variables. For this reason it is
+recommended that the user-supplied matcher code treats them as read-only
+variables.
+
+They are declared like state variables, just using the `udata` statement:
+
+    udata <int> min_data_width max_data_width
+    udata <IdString> data_port_name
+
+They are atomatically initialzed to the default constructed value of their type
+when ther pattern matcher object is constructed.
+
+Embedded C++ code
+-----------------
+
+Many statements in a `.pmg` file contain C++ code. However, there are some
+slight additions to regular C++/Yosys/RTLIL code that make it a bit easier to
+write matchers:
+
+- Identifiers starting with a dollar sign or backslash are automatically
+  converted to special IdString variables that are initialized when the
+  matcher object is constructed.
+
+- The `port(<cell>, <portname>)` function is a handy alias for
+  `sigmap(<cell>->getPort(<portname>))`.
+
+- Similarly `param(<cell>, <paramname>)` looks up a parameter on a cell.
+
+- The function `nusers(<sigspec>)` returns the number of different cells
+  connected to any of the given signal bits, plus one if any of the signal
+  bits is also a primary input or primary output.
+
+- In `code..endcode` blocks there exist `accept`, `reject`, and `branch`
+  statements.
+
+- In `index` statements there is a special `===` operator for the index
+  lookup.
+
+Matching cells
+--------------
+
+Cells are matched using `match..endmatch` blocks. For example:
+
+    match mul
+        if ff
+        select mul->type == $mul
+        select nusers(port(mul, \Y) == 2
+        index <SigSpec> port(mul, \Y) === port(ff, \D)
+        filter some_weird_function(mul) < other_weird_function(ff)
+        optional
+    endmatch
+
+A `match` block starts with `match <statevar>` and implicitly generates
+a state variable `<statevar>` of type `RTLIL::Cell*`.
+
+All statements in the match block are optional. (An empty match block
+would simply match each and every cell in the module.)
+
+The `if <expression>` statement makes the match block conditional. If
+`<expression>` evaluates to `false` then the match block will be ignored
+and the corresponding state variable is set to `nullptr`. In our example
+we only try to match the `mul` cell if the `ff` state variable points
+to a cell. (Presumably `ff` is provided by a prior `match` block.)
+
+The `select` lines are evaluated once for each cell when the matcher is
+initialized. A `match` block will only consider cells for which all `select`
+expressions evaluated to `true`. Note that the state variable corresponding to
+the match (in the example `mul`) is the only state variable that may be used
+`select` lines.
+
+Index lines are using the `index <type> expr1 === expr2` syntax.  `expr1` is
+evaluated during matcher initialization and the same restrictions apply as for
+`select` expressions. `expr2` is evaluated when the match is calulated. It is a
+function of any state variables assigned to by previous blocks. Both expression
+are converted to the given type and compared for equality. Only cells for which
+all `index` statements in the block pass are considered by the match.
+
+Note that `select` and `index` are fast operations. Thus `select` and `index`
+should be used whenever possible to create efficient matchers.
+
+Finally, `filter <expression>` narrows down the remaining list of cells. For
+performance reasons `filter` statements should only be used for things that
+can't be done using `select` and `index`.
+
+The `optional` statement marks optional matches. I.e. the matcher will also
+explore the case where `mul` is set to `nullptr`. Without the `optional`
+statement a match may only be assigned nullptr when one of the `if` expressions
+evaluates to `false`.
+
+Additional code
+---------------
+
+Interleaved with `match..endmatch` blocks there may be `code..endcode` blocks.
+Such a block starts with the keyword `code` followed by a list of state variables
+that the block may modify. For example:
+
+    code addAB sigS
+        if (addA) {
+            addAB = addA;
+            sigS = port(addA, \B);
+        }
+        if (addB) {
+            addAB = addB;
+            sigS = port(addB, \A);
+        }
+    endcode
+
+The special keyword `reject` can be used to reject the current state and
+backtrack. For example:
+
+    code
+        if (ffA && ffB) {
+            if (port(ffA, \CLK) != port(ffB, \CLK))
+                reject;
+            if (param(ffA, \CLK_POLARITY) != param(ffB, \CLK_POLARITY))
+                reject;
+        }
+    endcode
+
+Similarly, the special keyword `accept` can be used to accept the current
+state. (`accept` will not backtrack. This means it continues with the current
+branch and may accept a larger match later.)
+
+The special keyword `branch` can be used to explore different cases. Note that
+each code block has an implicit `branch` at the end. So most use-cases of the
+`branch` keyword need to end the block with `reject` to avoid the implicit
+branch at the end. For example:
+
+    state <int> mode
+
+    code mode
+        for (mode = 0; mode < 8; mode++)
+            branch;
+        reject;
+    endcode
+
+But in some cases it is more natural to utilize the implicit branch statement:
+
+    state <IdString> portAB
+
+    code portAB
+        portAB = \A;
+        branch;
+        portAB = \B;
+    endcode
+
+There is an implicit `code..endcode` block at the end of each `.pgm` file
+that just accepts everything that gets all the way there.
diff --git a/passes/pmgen/ice40_dsp.cc b/passes/pmgen/ice40_dsp.cc
new file mode 100644
index 000000000..3a054a463
--- /dev/null
+++ b/passes/pmgen/ice40_dsp.cc
@@ -0,0 +1,237 @@
+/*
+ *  yosys -- Yosys Open SYnthesis Suite
+ *
+ *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
+ *
+ *  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"
+#include "passes/pmgen/ice40_dsp_pm.h"
+
+USING_YOSYS_NAMESPACE
+PRIVATE_NAMESPACE_BEGIN
+
+void create_ice40_dsp(ice40_dsp_pm &pm)
+{
+#if 0
+	log("\n");
+	log("ffA:   %s\n", log_id(pm.st.ffA, "--"));
+	log("ffB:   %s\n", log_id(pm.st.ffB, "--"));
+	log("mul:   %s\n", log_id(pm.st.mul, "--"));
+	log("ffY:   %s\n", log_id(pm.st.ffY, "--"));
+	log("addAB: %s\n", log_id(pm.st.addAB, "--"));
+	log("muxAB: %s\n", log_id(pm.st.muxAB, "--"));
+	log("ffS:   %s\n", log_id(pm.st.ffS, "--"));
+#endif
+
+	log("Checking %s.%s for iCE40 DSP inference.\n", log_id(pm.module), log_id(pm.st.mul));
+
+	if (GetSize(pm.st.sigA) > 16) {
+		log("  input A (%s) is too large (%d > 16).\n", log_signal(pm.st.sigA), GetSize(pm.st.sigA));
+		return;
+	}
+
+	if (GetSize(pm.st.sigB) > 16) {
+		log("  input B (%s) is too large (%d > 16).\n", log_signal(pm.st.sigB), GetSize(pm.st.sigB));
+		return;
+	}
+
+	if (GetSize(pm.st.sigS) > 32) {
+		log("  accumulator (%s) is too large (%d > 32).\n", log_signal(pm.st.sigS), GetSize(pm.st.sigS));
+		return;
+	}
+
+	if (GetSize(pm.st.sigY) > 32) {
+		log("  output (%s) is too large (%d > 32).\n", log_signal(pm.st.sigY), GetSize(pm.st.sigY));
+		return;
+	}
+
+	bool mul_signed = pm.st.mul->getParam("\\A_SIGNED").as_bool();
+
+	if (mul_signed) {
+		log("  inference of signed iCE40 DSP arithmetic is currently not supported.\n");
+		return;
+	}
+
+	log("  replacing $mul with SB_MAC16 cell.\n");
+
+	Cell *cell = pm.module->addCell(NEW_ID, "\\SB_MAC16");
+	pm.module->swap_names(cell, pm.st.mul);
+
+	// SB_MAC16 Input Interface
+
+	SigSpec A = pm.st.sigA;
+	A.extend_u0(16, mul_signed);
+
+	SigSpec B = pm.st.sigB;
+	B.extend_u0(16, mul_signed);
+
+	SigSpec CD;
+	if (pm.st.muxA)
+		CD = pm.st.muxA->getPort("\\B");
+	if (pm.st.muxB)
+		CD = pm.st.muxB->getPort("\\A");
+	CD.extend_u0(32, mul_signed);
+
+	cell->setPort("\\A", A);
+	cell->setPort("\\B", B);
+	cell->setPort("\\C", CD.extract(0, 16));
+	cell->setPort("\\D", CD.extract(16, 16));
+
+	cell->setParam("\\A_REG", pm.st.ffA ? State::S1 : State::S0);
+	cell->setParam("\\B_REG", pm.st.ffB ? State::S1 : State::S0);
+
+	cell->setPort("\\AHOLD", State::S0);
+	cell->setPort("\\BHOLD", State::S0);
+	cell->setPort("\\CHOLD", State::S0);
+	cell->setPort("\\DHOLD", State::S0);
+
+	cell->setPort("\\IRSTTOP", State::S0);
+	cell->setPort("\\IRSTBOT", State::S0);
+
+	if (pm.st.clock_vld)
+	{
+		cell->setPort("\\CLK", pm.st.clock);
+		cell->setPort("\\CE", State::S1);
+		cell->setParam("\\NEG_TRIGGER", pm.st.clock_pol ? State::S0 : State::S1);
+
+		log("  clock: %s (%s)", log_signal(pm.st.clock), pm.st.clock_pol ? "posedge" : "negedge");
+
+		if (pm.st.ffA)
+			log(" ffA:%s", log_id(pm.st.ffA));
+
+		if (pm.st.ffB)
+			log(" ffB:%s", log_id(pm.st.ffB));
+
+		if (pm.st.ffY)
+			log(" ffY:%s", log_id(pm.st.ffY));
+
+		if (pm.st.ffS)
+			log(" ffS:%s", log_id(pm.st.ffS));
+
+		log("\n");
+	}
+	else
+	{
+		cell->setPort("\\CLK", State::S0);
+		cell->setPort("\\CE", State::S0);
+		cell->setParam("\\NEG_TRIGGER", State::S0);
+	}
+
+	// SB_MAC16 Cascade Interface
+
+	cell->setPort("\\SIGNEXTIN", State::Sx);
+	cell->setPort("\\SIGNEXTOUT", pm.module->addWire(NEW_ID));
+
+	cell->setPort("\\CI", State::Sx);
+	cell->setPort("\\CO", pm.module->addWire(NEW_ID));
+
+	cell->setPort("\\ACCUMCI", State::Sx);
+	cell->setPort("\\ACCUMCO", pm.module->addWire(NEW_ID));
+
+	// SB_MAC16 Output Interface
+
+	SigSpec O = pm.st.ffS ? pm.st.sigS : pm.st.sigY;
+	if (GetSize(O) < 32)
+		O.append(pm.module->addWire(NEW_ID, 32-GetSize(O)));
+
+	cell->setPort("\\O", O);
+
+	if (pm.st.addAB) {
+		log("  accumulator %s (%s)\n", log_id(pm.st.addAB), log_id(pm.st.addAB->type));
+		cell->setPort("\\ADDSUBTOP", pm.st.addAB->type == "$add" ? State::S0 : State::S1);
+		cell->setPort("\\ADDSUBBOT", pm.st.addAB->type == "$add" ? State::S0 : State::S1);
+	} else {
+		cell->setPort("\\ADDSUBTOP", State::S0);
+		cell->setPort("\\ADDSUBBOT", State::S0);
+	}
+
+	cell->setPort("\\ORSTTOP", State::S0);
+	cell->setPort("\\ORSTBOT", State::S0);
+
+	cell->setPort("\\OHOLDTOP", State::S0);
+	cell->setPort("\\OHOLDBOT", State::S0);
+
+	SigSpec acc_reset = State::S0;
+	if (pm.st.muxA)
+		acc_reset = pm.st.muxA->getPort("\\S");
+	if (pm.st.muxB)
+		acc_reset = pm.module->Not(NEW_ID, pm.st.muxB->getPort("\\S"));
+
+	cell->setPort("\\OLOADTOP", acc_reset);
+	cell->setPort("\\OLOADBOT", acc_reset);
+
+	// SB_MAC16 Remaining Parameters
+
+	cell->setParam("\\C_REG", State::S0);
+	cell->setParam("\\D_REG", State::S0);
+
+	cell->setParam("\\TOP_8x8_MULT_REG", pm.st.ffY ? State::S1 : State::S0);
+	cell->setParam("\\BOT_8x8_MULT_REG", pm.st.ffY ? State::S1 : State::S0);
+	cell->setParam("\\PIPELINE_16x16_MULT_REG1", pm.st.ffY ? State::S1 : State::S0);
+	cell->setParam("\\PIPELINE_16x16_MULT_REG2", State::S0);
+
+	cell->setParam("\\TOPOUTPUT_SELECT", Const(pm.st.ffS ? 1 : 3, 2));
+	cell->setParam("\\TOPADDSUB_LOWERINPUT", Const(2, 2));
+	cell->setParam("\\TOPADDSUB_UPPERINPUT", State::S0);
+	cell->setParam("\\TOPADDSUB_CARRYSELECT", Const(3, 2));
+
+	cell->setParam("\\BOTOUTPUT_SELECT", Const(pm.st.ffS ? 1 : 3, 2));
+	cell->setParam("\\BOTADDSUB_LOWERINPUT", Const(2, 2));
+	cell->setParam("\\BOTADDSUB_UPPERINPUT", State::S0);
+	cell->setParam("\\BOTADDSUB_CARRYSELECT", Const(0, 2));
+
+	cell->setParam("\\MODE_8x8", State::S0);
+	cell->setParam("\\A_SIGNED", mul_signed ? State::S1 : State::S0);
+	cell->setParam("\\B_SIGNED", mul_signed ? State::S1 : State::S0);
+
+	pm.autoremove(pm.st.mul);
+	pm.autoremove(pm.st.ffY);
+	pm.autoremove(pm.st.ffS);
+}
+
+struct Ice40DspPass : public Pass {
+	Ice40DspPass() : Pass("ice40_dsp", "iCE40: map multipliers") { }
+	void help() YS_OVERRIDE
+	{
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("\n");
+		log("    ice40_dsp [options] [selection]\n");
+		log("\n");
+		log("Map multipliers and multiply-accumulate blocks to iCE40 DSP resources.\n");
+		log("\n");
+	}
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	{
+		log_header(design, "Executing ICE40_DSP pass (map multipliers).\n");
+
+		size_t argidx;
+		for (argidx = 1; argidx < args.size(); argidx++)
+		{
+			// if (args[argidx] == "-singleton") {
+			// 	singleton_mode = true;
+			// 	continue;
+			// }
+			break;
+		}
+		extra_args(args, argidx, design);
+
+		for (auto module : design->selected_modules())
+			ice40_dsp_pm(module, module->selected_cells()).run(create_ice40_dsp);
+	}
+} Ice40DspPass;
+
+PRIVATE_NAMESPACE_END
diff --git a/passes/pmgen/ice40_dsp.pmg b/passes/pmgen/ice40_dsp.pmg
new file mode 100644
index 000000000..96c62e313
--- /dev/null
+++ b/passes/pmgen/ice40_dsp.pmg
@@ -0,0 +1,160 @@
+state <SigBit> clock
+state <bool> clock_pol clock_vld
+state <SigSpec> sigA sigB sigY sigS
+state <Cell*> addAB muxAB
+
+match mul
+	select mul->type.in($mul)
+	select GetSize(mul->getPort(\A)) + GetSize(mul->getPort(\B)) > 10
+	select GetSize(mul->getPort(\Y)) > 10
+endmatch
+
+match ffA
+	select ffA->type.in($dff)
+	// select nusers(port(ffA, \Q)) == 2
+	index <SigSpec> port(ffA, \Q) === port(mul, \A)
+	optional
+endmatch
+
+code sigA clock clock_pol clock_vld
+	sigA = port(mul, \A);
+
+	if (ffA) {
+		sigA = port(ffA, \D);
+
+		clock = port(ffA, \CLK).as_bit();
+		clock_pol = param(ffA, \CLK_POLARITY).as_bool();
+		clock_vld = true;
+	}
+endcode
+
+match ffB
+	select ffB->type.in($dff)
+	// select nusers(port(ffB, \Q)) == 2
+	index <SigSpec> port(ffB, \Q) === port(mul, \B)
+	optional
+endmatch
+
+code sigB clock clock_pol clock_vld
+	sigB = port(mul, \B);
+
+	if (ffB) {
+		sigB = port(ffB, \D);
+		SigBit c = port(ffB, \CLK).as_bit();
+		bool cp = param(ffB, \CLK_POLARITY).as_bool();
+
+		if (clock_vld && (c != clock || cp != clock_pol))
+			reject;
+
+		clock = c;
+		clock_pol = cp;
+		clock_vld = true;
+	}
+endcode
+
+match ffY
+	select ffY->type.in($dff)
+	select nusers(port(ffY, \D)) == 2
+	index <SigSpec> port(ffY, \D) === port(mul, \Y)
+	optional
+endmatch
+
+code sigY clock clock_pol clock_vld
+	sigY = port(mul, \Y);
+
+	if (ffY) {
+		sigY = port(ffY, \Q);
+		SigBit c = port(ffY, \CLK).as_bit();
+		bool cp = param(ffY, \CLK_POLARITY).as_bool();
+
+		if (clock_vld && (c != clock || cp != clock_pol))
+			reject;
+
+		clock = c;
+		clock_pol = cp;
+		clock_vld = true;
+	}
+endcode
+
+match addA
+	select addA->type.in($add)
+	select nusers(port(addA, \A)) == 2
+	index <SigSpec> port(addA, \A) === sigY
+	optional
+endmatch
+
+match addB
+	if !addA
+	select addB->type.in($add, $sub)
+	select nusers(port(addB, \B)) == 2
+	index <SigSpec> port(addB, \B) === sigY
+	optional
+endmatch
+
+code addAB sigS
+	if (addA) {
+		addAB = addA;
+		sigS = port(addA, \B);
+	}
+	if (addB) {
+		addAB = addB;
+		sigS = port(addB, \A);
+	}
+	if (addAB) {
+		int natural_mul_width = GetSize(sigA) + GetSize(sigB);
+		int actual_mul_width = GetSize(sigY);
+		int actual_acc_width = GetSize(sigS);
+
+		if ((actual_acc_width > actual_mul_width) && (natural_mul_width > actual_mul_width))
+			reject;
+		if ((actual_acc_width != actual_mul_width) && (param(mul, \A_SIGNED).as_bool() != param(addAB, \A_SIGNED).as_bool()))
+			reject;
+	}
+endcode
+
+match muxA
+	if addAB
+	select muxA->type.in($mux)
+	select nusers(port(muxA, \A)) == 2
+	index <SigSpec> port(muxA, \A) === port(addAB, \Y)
+	optional
+endmatch
+
+match muxB
+	if addAB
+	if !muxA
+	select muxB->type.in($mux)
+	select nusers(port(muxB, \B)) == 2
+	index <SigSpec> port(muxB, \B) === port(addAB, \Y)
+	optional
+endmatch
+
+code muxAB
+	muxAB = addAB;
+	if (muxA)
+		muxAB = muxA;
+	if (muxB)
+		muxAB = muxB;
+endcode
+
+match ffS
+	if muxAB
+	select ffS->type.in($dff)
+	select nusers(port(ffS, \D)) == 2
+	index <SigSpec> port(ffS, \D) === port(muxAB, \Y)
+	index <SigSpec> port(ffS, \Q) === sigS
+endmatch
+
+code clock clock_pol clock_vld
+	if (ffS) {
+		SigBit c = port(ffS, \CLK).as_bit();
+		bool cp = param(ffS, \CLK_POLARITY).as_bool();
+
+		if (clock_vld && (c != clock || cp != clock_pol))
+			reject;
+
+		clock = c;
+		clock_pol = cp;
+		clock_vld = true;
+	}
+endcode
diff --git a/passes/pmgen/pmgen.py b/passes/pmgen/pmgen.py
new file mode 100644
index 000000000..e688a4567
--- /dev/null
+++ b/passes/pmgen/pmgen.py
@@ -0,0 +1,482 @@
+#!/usr/bin/env python3
+
+import re
+import sys
+import pprint
+
+pp = pprint.PrettyPrinter(indent=4)
+
+prefix = sys.argv[1]
+
+state_types = dict()
+udata_types = dict()
+blocks = list()
+ids = dict()
+
+def rewrite_cpp(s):
+    t = list()
+    i = 0
+    while i < len(s):
+        if s[i] in ("'", '"') and i + 1 < len(s):
+            j = i + 1
+            while j + 1 < len(s) and s[j] != s[i]:
+                if s[j] == '\\' and j + 1 < len(s):
+                    j += 1
+                j += 1
+            t.append(s[i:j+1])
+            i = j + 1
+            continue
+
+        if s[i] in ('$', '\\') and i + 1 < len(s):
+            j = i + 1
+            while True:
+                if j == len(s):
+                    j -= 1
+                    break
+                if ord('a') <= ord(s[j]) <= ord('z'):
+                    j += 1
+                    continue
+                if ord('A') <= ord(s[j]) <= ord('Z'):
+                    j += 1
+                    continue
+                if ord('0') <= ord(s[j]) <= ord('9'):
+                    j += 1
+                    continue
+                if s[j] == '_':
+                    j += 1
+                    continue
+                j -= 1
+                break
+
+            n = s[i:j+1]
+            i = j + 1
+
+            if n[0] == '$':
+                v = "id_d_" + n[1:]
+            else:
+                v = "id_b_" + n[1:]
+
+            if v not in ids:
+                ids[v] = n
+            else:
+                assert ids[v] == n
+
+            t.append(v)
+            continue
+
+        if s[i] == "\t":
+            t.append("  ")
+        else:
+            t.append(s[i])
+
+        i += 1
+
+    return "".join(t)
+
+with open("%s.pmg" % prefix, "r") as f:
+    while True:
+        line = f.readline()
+        if line == "": break
+        line = line.strip()
+
+        cmd = line.split()
+        if len(cmd) == 0 or cmd[0].startswith("//"): continue
+        cmd = cmd[0]
+        
+        if cmd == "state":
+            m = re.match(r"^state\s+<(.*?)>\s+(([A-Za-z_][A-Za-z_0-9]*\s+)*[A-Za-z_][A-Za-z_0-9]*)\s*$", line)
+            assert m
+            type_str = m.group(1)
+            states_str = m.group(2)
+            for s in re.split(r"\s+", states_str):
+                assert s not in state_types
+                state_types[s] = type_str
+            continue
+
+        if cmd == "udata":
+            m = re.match(r"^udata\s+<(.*?)>\s+(([A-Za-z_][A-Za-z_0-9]*\s+)*[A-Za-z_][A-Za-z_0-9]*)\s*$", line)
+            assert m
+            type_str = m.group(1)
+            udatas_str = m.group(2)
+            for s in re.split(r"\s+", udatas_str):
+                assert s not in udata_types
+                udata_types[s] = type_str
+            continue
+
+        if cmd == "match":
+            block = dict()
+            block["type"] = "match"
+
+            line = line.split()
+            assert len(line) == 2
+            assert line[1] not in state_types
+            block["cell"] = line[1]
+            state_types[line[1]] = "Cell*";
+
+            block["if"] = list()
+            block["select"] = list()
+            block["index"] = list()
+            block["filter"] = list()
+            block["optional"] = False
+
+            while True:
+                l = f.readline()
+                assert l != ""
+                a = l.split()
+                if len(a) == 0 or a[0].startswith("//"): continue
+                if a[0] == "endmatch": break
+
+                if a[0] == "if":
+                    b = l.lstrip()[2:]
+                    block["if"].append(rewrite_cpp(b.strip()))
+                    continue
+
+                if a[0] == "select":
+                    b = l.lstrip()[6:]
+                    block["select"].append(rewrite_cpp(b.strip()))
+                    continue
+
+                if a[0] == "index":
+                    m = re.match(r"^\s*index\s+<(.*?)>\s+(.*?)\s*===\s*(.*?)\s*$", l)
+                    assert m
+                    block["index"].append((m.group(1), rewrite_cpp(m.group(2)), rewrite_cpp(m.group(3))))
+                    continue
+
+                if a[0] == "filter":
+                    b = l.lstrip()[6:]
+                    block["filter"].append(rewrite_cpp(b.strip()))
+                    continue
+
+                if a[0] == "optional":
+                    block["optional"] = True
+                    continue
+
+                assert False
+
+            blocks.append(block)
+
+        if cmd == "code":
+            block = dict()
+            block["type"] = "code"
+            block["code"] = list()
+            block["states"] = set()
+
+            for s in line.split()[1:]:
+                assert s in state_types
+                block["states"].add(s)
+
+            while True:
+                l = f.readline()
+                assert l != ""
+                a = l.split()
+                if len(a) == 0: continue
+                if a[0] == "endcode": break
+
+                block["code"].append(rewrite_cpp(l.rstrip()))
+
+            blocks.append(block)
+
+with open("%s_pm.h" % prefix, "w") as f:
+    print("// Generated by pmgen.py from {}.pgm".format(prefix), file=f)
+    print("", file=f)
+
+    print("#include \"kernel/yosys.h\"", file=f)
+    print("#include \"kernel/sigtools.h\"", file=f)
+    print("", file=f)
+
+    print("YOSYS_NAMESPACE_BEGIN", file=f)
+    print("", file=f)
+
+    print("struct {}_pm {{".format(prefix), file=f)
+    print("  Module *module;", file=f)
+    print("  SigMap sigmap;", file=f)
+    print("  std::function<void()> on_accept;".format(prefix), file=f)
+    print("", file=f)
+
+    for index in range(len(blocks)):
+        block = blocks[index]
+        if block["type"] == "match":
+            index_types = list()
+            for entry in block["index"]:
+                index_types.append(entry[0])
+            print("  typedef std::tuple<{}> index_{}_key_type;".format(", ".join(index_types), index), file=f)
+            print("  dict<index_{}_key_type, vector<Cell*>> index_{};".format(index, index), file=f)
+    print("  dict<SigBit, pool<Cell*>> sigusers;", file=f)
+    print("  pool<Cell*> blacklist_cells;", file=f)
+    print("  pool<Cell*> autoremove_cells;", file=f)
+    print("  bool blacklist_dirty;", file=f)
+    print("  int rollback;", file=f)
+    print("", file=f)
+
+    print("  struct state_t {", file=f)
+    for s, t in sorted(state_types.items()):
+        print("    {} {};".format(t, s), file=f)
+    print("  } st;", file=f)
+    print("", file=f)
+
+    print("  struct udata_t {", file=f)
+    for s, t in sorted(udata_types.items()):
+        print("    {} {};".format(t, s), file=f)
+    print("  } ud;", file=f)
+    print("", file=f)
+
+    for v, n in sorted(ids.items()):
+        if n[0] == "\\":
+            print("  IdString {}{{\"\\{}\"}};".format(v, n), file=f)
+        else:
+            print("  IdString {}{{\"{}\"}};".format(v, n), file=f)
+    print("", file=f)
+
+    print("  void add_siguser(const SigSpec &sig, Cell *cell) {", file=f)
+    print("    for (auto bit : sigmap(sig)) {", file=f)
+    print("      if (bit.wire == nullptr) continue;", file=f)
+    print("      if (sigusers.count(bit) == 0 && bit.wire->port_id)", file=f)
+    print("        sigusers[bit].insert(nullptr);", file=f)
+    print("      sigusers[bit].insert(cell);", file=f)
+    print("    }", file=f)
+    print("  }", file=f)
+    print("", file=f)
+
+    print("  void blacklist(Cell *cell) {", file=f)
+    print("    if (cell != nullptr) {", file=f)
+    print("      if (blacklist_cells.insert(cell).second)", file=f)
+    print("        blacklist_dirty = true;", file=f)
+    print("    }", file=f)
+    print("  }", file=f)
+    print("", file=f)
+
+    print("  void autoremove(Cell *cell) {", file=f)
+    print("    if (cell != nullptr) {", file=f)
+    print("      if (blacklist_cells.insert(cell).second)", file=f)
+    print("        blacklist_dirty = true;", file=f)
+    print("      autoremove_cells.insert(cell);", file=f)
+    print("    }", file=f)
+    print("  }", file=f)
+    print("", file=f)
+
+    print("  void check_blacklist() {", file=f)
+    print("    if (!blacklist_dirty)", file=f)
+    print("      return;", file=f)
+    print("    blacklist_dirty = false;", file=f)
+    for index in range(len(blocks)):
+        block = blocks[index]
+        if block["type"] == "match":
+            print("    if (st.{} != nullptr && blacklist_cells.count(st.{})) {{".format(block["cell"], block["cell"]), file=f)
+            print("      rollback = {};".format(index+1), file=f)
+            print("      return;", file=f)
+            print("    }", file=f)
+    print("    rollback = 0;", file=f)
+    print("  }", file=f)
+    print("", file=f)
+
+    print("  SigSpec port(Cell *cell, IdString portname) {", file=f)
+    print("    return sigmap(cell->getPort(portname));", file=f)
+    print("  }", file=f)
+    print("", file=f)
+
+    print("  Const param(Cell *cell, IdString paramname) {", file=f)
+    print("    return cell->getParam(paramname);", file=f)
+    print("  }", file=f)
+    print("", file=f)
+
+    print("  int nusers(const SigSpec &sig) {", file=f)
+    print("    pool<Cell*> users;", file=f)
+    print("    for (auto bit : sigmap(sig))", file=f)
+    print("      for (auto user : sigusers[bit])", file=f)
+    print("        users.insert(user);", file=f)
+    print("    return GetSize(users);", file=f)
+    print("  }", file=f)
+    print("", file=f)
+
+    print("  {}_pm(Module *module, const vector<Cell*> &cells) :".format(prefix), file=f)
+    print("      module(module), sigmap(module) {", file=f)
+    for s, t in sorted(udata_types.items()):
+        if t.endswith("*"):
+            print("    ud.{} = nullptr;".format(s), file=f)
+        else:
+            print("    ud.{} = {}();".format(s, t), file=f)
+    print("    for (auto cell : module->cells()) {", file=f)
+    print("      for (auto &conn : cell->connections())", file=f)
+    print("        add_siguser(conn.second, cell);", file=f)
+    print("    }", file=f)
+    print("    for (auto cell : cells) {", file=f)
+
+    for index in range(len(blocks)):
+        block = blocks[index]
+        if block["type"] == "match":
+            print("      do {", file=f)
+            print("        Cell *{} = cell;".format(block["cell"]), file=f)
+            for expr in block["select"]:
+                print("        if (!({})) break;".format(expr), file=f)
+            print("        index_{}_key_type key;".format(index), file=f)
+            for field, entry in enumerate(block["index"]):
+                print("        std::get<{}>(key) = {};".format(field, entry[1]), file=f)
+            print("        index_{}[key].push_back(cell);".format(index), file=f)
+            print("      } while (0);", file=f)
+
+    print("    }", file=f)
+    print("  }", file=f)
+    print("", file=f)
+
+    print("  ~{}_pm() {{".format(prefix), file=f)
+    print("    for (auto cell : autoremove_cells)", file=f)
+    print("      module->remove(cell);", file=f)
+    print("  }", file=f)
+    print("", file=f)
+
+    print("  void run(std::function<void()> on_accept_f) {", file=f)
+    print("    on_accept = on_accept_f;", file=f)
+    print("    rollback = 0;", file=f)
+    print("    blacklist_dirty = false;", file=f)
+    for s, t in sorted(state_types.items()):
+        if t.endswith("*"):
+            print("    st.{} = nullptr;".format(s), file=f)
+        else:
+            print("    st.{} = {}();".format(s, t), file=f)
+    print("    block_0();", file=f)
+    print("  }", file=f)
+    print("", file=f)
+
+    print("  void run(std::function<void({}_pm&)> on_accept_f) {{".format(prefix), file=f)
+    print("    run([&](){on_accept_f(*this);});", file=f)
+    print("  }", file=f)
+    print("", file=f)
+
+    for index in range(len(blocks)):
+        block = blocks[index]
+
+        print("  void block_{}() {{".format(index), file=f)
+
+        const_st = set()
+        nonconst_st = set()
+        restore_st = set()
+
+        for i in range(index):
+            if blocks[i]["type"] == "code":
+                for s in blocks[i]["states"]:
+                    const_st.add(s)
+            elif blocks[i]["type"] == "match":
+                const_st.add(blocks[i]["cell"])
+            else:
+                assert False
+
+        if block["type"] == "code":
+            for s in block["states"]:
+                if s in const_st:
+                    const_st.remove(s)
+                    restore_st.add(s)
+                nonconst_st.add(s)
+        elif block["type"] == "match":
+            s = block["cell"]
+            assert s not in const_st
+            nonconst_st.add(s)
+        else:
+            assert False
+
+        for s in sorted(const_st):
+            t = state_types[s]
+            if t.endswith("*"):
+                print("    {} const &{} YS_ATTRIBUTE(unused) = st.{};".format(t, s, s), file=f)
+            else:
+                print("    const {} &{} YS_ATTRIBUTE(unused) = st.{};".format(t, s, s), file=f)
+
+        for s in sorted(nonconst_st):
+            t = state_types[s]
+            print("    {} &{} YS_ATTRIBUTE(unused) = st.{};".format(t, s, s), file=f)
+
+        if len(restore_st):
+            print("", file=f)
+            for s in sorted(restore_st):
+                t = state_types[s]
+                print("    {} backup_{} = {};".format(t, s, s), file=f)
+
+        if block["type"] == "code":
+            print("", file=f)
+            print("    do {", file=f)
+            print("#define reject do { check_blacklist(); goto rollback_label; } while(0)", file=f)
+            print("#define accept do { on_accept(); check_blacklist(); if (rollback) goto rollback_label; } while(0)", file=f)
+            print("#define branch do {{ block_{}(); if (rollback) goto rollback_label; }} while(0)".format(index+1), file=f)
+
+            for line in block["code"]:
+                print("    " + line, file=f)
+
+            print("", file=f)
+            print("      block_{}();".format(index+1), file=f)
+            print("#undef reject", file=f)
+            print("#undef accept", file=f)
+            print("#undef branch", file=f)
+            print("    } while (0);", file=f)
+            print("", file=f)
+            print("rollback_label:", file=f)
+            print("    YS_ATTRIBUTE(unused);", file=f)
+
+            if len(restore_st) or len(nonconst_st):
+                print("", file=f)
+                for s in sorted(restore_st):
+                    t = state_types[s]
+                    print("    {} = backup_{};".format(s, s), file=f)
+                for s in sorted(nonconst_st):
+                    if s not in restore_st:
+                        t = state_types[s]
+                        if t.endswith("*"):
+                            print("    {} = nullptr;".format(s), file=f)
+                        else:
+                            print("    {} = {}();".format(s, t), file=f)
+
+        elif block["type"] == "match":
+            assert len(restore_st) == 0
+
+            if len(block["if"]):
+                for expr in block["if"]:
+                    print("", file=f)
+                    print("    if (!({})) {{".format(expr), file=f)
+                    print("      {} = nullptr;".format(block["cell"]), file=f)
+                    print("      block_{}();".format(index+1), file=f)
+                    print("      return;", file=f)
+                    print("    }", file=f)
+
+            print("", file=f)
+            print("    index_{}_key_type key;".format(index), file=f)
+            for field, entry in enumerate(block["index"]):
+                print("    std::get<{}>(key) = {};".format(field, entry[2]), file=f)
+            print("    const vector<Cell*> &cells = index_{}[key];".format(index), file=f)
+
+            print("", file=f)
+            print("    for (int idx = 0; idx < GetSize(cells); idx++) {", file=f)
+            print("      {} = cells[idx];".format(block["cell"]), file=f)
+            print("      if (blacklist_cells.count({})) continue;".format(block["cell"]), file=f)
+            for expr in block["filter"]:
+                print("      if (!({})) continue;".format(expr), file=f)
+            print("      block_{}();".format(index+1), file=f)
+            print("      if (rollback) {", file=f)
+            print("        if (rollback != {}) {{".format(index+1), file=f)
+            print("          {} = nullptr;".format(block["cell"]), file=f)
+            print("          return;", file=f)
+            print("        }", file=f)
+            print("        rollback = 0;", file=f)
+            print("      }", file=f)
+            print("    }", file=f)
+
+            print("", file=f)
+            print("    {} = nullptr;".format(block["cell"]), file=f)
+
+            if block["optional"]:
+                print("    block_{}();".format(index+1), file=f)
+
+        else:
+            assert False
+
+
+        print("  }", file=f)
+        print("", file=f)
+
+    print("  void block_{}() {{".format(len(blocks)), file=f)
+    print("    on_accept();", file=f)
+    print("    check_blacklist();", file=f)
+    print("  }", file=f)
+    print("};", file=f)
+
+    print("", file=f)
+    print("YOSYS_NAMESPACE_END", file=f)
+
+# pp.pprint(blocks)
diff --git a/passes/techmap/abc.cc b/passes/techmap/abc.cc
index d2d15a4a9..21b70f492 100644
--- a/passes/techmap/abc.cc
+++ b/passes/techmap/abc.cc
@@ -327,8 +327,26 @@ void extract_cell(RTLIL::Cell *cell, bool keepff)
 	}
 }
 
-std::string remap_name(RTLIL::IdString abc_name)
+std::string remap_name(RTLIL::IdString abc_name, RTLIL::Wire **orig_wire = nullptr)
 {
+	std::string abc_sname = abc_name.substr(1);
+	if (abc_sname.substr(0, 5) == "ys__n") {
+		int sid = std::stoi(abc_sname.substr(5));
+		bool inv = abc_sname.back() == 'v';
+		for (auto sig : signal_list) {
+			if (sig.id == sid && sig.bit.wire != nullptr) {
+				std::stringstream sstr;
+				sstr << "$abc$" << map_autoidx << "$" << sig.bit.wire->name.substr(1);
+				if (sig.bit.wire->width != 1)
+					sstr << "[" << sig.bit.offset << "]";
+				if (inv)
+					sstr << "_inv";
+				if (orig_wire != nullptr)
+					*orig_wire = sig.bit.wire;
+				return sstr.str();
+			}
+		}
+	}
 	std::stringstream sstr;
 	sstr << "$abc$" << map_autoidx << "$" << abc_name.substr(1);
 	return sstr.str();
@@ -353,12 +371,12 @@ void dump_loop_graph(FILE *f, int &nr, std::map<int, std::set<int>> &edges, std:
 	}
 
 	for (auto n : nodes)
-		fprintf(f, "  n%d [label=\"%s\\nid=%d, count=%d\"%s];\n", n, log_signal(signal_list[n].bit),
+		fprintf(f, "  ys__n%d [label=\"%s\\nid=%d, count=%d\"%s];\n", n, log_signal(signal_list[n].bit),
 				n, in_counts[n], workpool.count(n) ? ", shape=box" : "");
 
 	for (auto &e : edges)
 	for (auto n : e.second)
-		fprintf(f, "  n%d -> n%d;\n", e.first, n);
+		fprintf(f, "  ys__n%d -> ys__n%d;\n", e.first, n);
 
 	fprintf(f, "}\n");
 }
@@ -624,7 +642,7 @@ struct abc_output_filter
 void abc_module(RTLIL::Design *design, RTLIL::Module *current_module, std::string script_file, std::string exe_file,
 		std::string liberty_file, std::string constr_file, bool cleanup, vector<int> lut_costs, bool dff_mode, std::string clk_str,
 		bool keepff, std::string delay_target, std::string sop_inputs, std::string sop_products, std::string lutin_shared, bool fast_mode,
-		const std::vector<RTLIL::Cell*> &cells, bool show_tempdir, bool sop_mode)
+		const std::vector<RTLIL::Cell*> &cells, bool show_tempdir, bool sop_mode, bool abc_dress)
 {
 	module = current_module;
 	map_autoidx = autoidx++;
@@ -728,7 +746,8 @@ void abc_module(RTLIL::Design *design, RTLIL::Module *current_module, std::strin
 
 	for (size_t pos = abc_script.find("{S}"); pos != std::string::npos; pos = abc_script.find("{S}", pos))
 		abc_script = abc_script.substr(0, pos) + lutin_shared + abc_script.substr(pos+3);
-
+	if (abc_dress)
+		abc_script += "; dress";
 	abc_script += stringf("; write_blif %s/output.blif", tempdir_name.c_str());
 	abc_script = add_echos_to_abc_cmd(abc_script);
 
@@ -784,7 +803,7 @@ void abc_module(RTLIL::Design *design, RTLIL::Module *current_module, std::strin
 	for (auto &si : signal_list) {
 		if (!si.is_port || si.type != G(NONE))
 			continue;
-		fprintf(f, " n%d", si.id);
+		fprintf(f, " ys__n%d", si.id);
 		pi_map[count_input++] = log_signal(si.bit);
 	}
 	if (count_input == 0)
@@ -796,17 +815,17 @@ void abc_module(RTLIL::Design *design, RTLIL::Module *current_module, std::strin
 	for (auto &si : signal_list) {
 		if (!si.is_port || si.type == G(NONE))
 			continue;
-		fprintf(f, " n%d", si.id);
+		fprintf(f, " ys__n%d", si.id);
 		po_map[count_output++] = log_signal(si.bit);
 	}
 	fprintf(f, "\n");
 
 	for (auto &si : signal_list)
-		fprintf(f, "# n%-5d %s\n", si.id, log_signal(si.bit));
+		fprintf(f, "# ys__n%-5d %s\n", si.id, log_signal(si.bit));
 
 	for (auto &si : signal_list) {
 		if (si.bit.wire == NULL) {
-			fprintf(f, ".names n%d\n", si.id);
+			fprintf(f, ".names ys__n%d\n", si.id);
 			if (si.bit == RTLIL::State::S1)
 				fprintf(f, "1\n");
 		}
@@ -815,68 +834,68 @@ void abc_module(RTLIL::Design *design, RTLIL::Module *current_module, std::strin
 	int count_gates = 0;
 	for (auto &si : signal_list) {
 		if (si.type == G(BUF)) {
-			fprintf(f, ".names n%d n%d\n", si.in1, si.id);
+			fprintf(f, ".names ys__n%d ys__n%d\n", si.in1, si.id);
 			fprintf(f, "1 1\n");
 		} else if (si.type == G(NOT)) {
-			fprintf(f, ".names n%d n%d\n", si.in1, si.id);
+			fprintf(f, ".names ys__n%d ys__n%d\n", si.in1, si.id);
 			fprintf(f, "0 1\n");
 		} else if (si.type == G(AND)) {
-			fprintf(f, ".names n%d n%d n%d\n", si.in1, si.in2, si.id);
+			fprintf(f, ".names ys__n%d ys__n%d ys__n%d\n", si.in1, si.in2, si.id);
 			fprintf(f, "11 1\n");
 		} else if (si.type == G(NAND)) {
-			fprintf(f, ".names n%d n%d n%d\n", si.in1, si.in2, si.id);
+			fprintf(f, ".names ys__n%d ys__n%d ys__n%d\n", si.in1, si.in2, si.id);
 			fprintf(f, "0- 1\n");
 			fprintf(f, "-0 1\n");
 		} else if (si.type == G(OR)) {
-			fprintf(f, ".names n%d n%d n%d\n", si.in1, si.in2, si.id);
+			fprintf(f, ".names ys__n%d ys__n%d ys__n%d\n", si.in1, si.in2, si.id);
 			fprintf(f, "-1 1\n");
 			fprintf(f, "1- 1\n");
 		} else if (si.type == G(NOR)) {
-			fprintf(f, ".names n%d n%d n%d\n", si.in1, si.in2, si.id);
+			fprintf(f, ".names ys__n%d ys__n%d ys__n%d\n", si.in1, si.in2, si.id);
 			fprintf(f, "00 1\n");
 		} else if (si.type == G(XOR)) {
-			fprintf(f, ".names n%d n%d n%d\n", si.in1, si.in2, si.id);
+			fprintf(f, ".names ys__n%d ys__n%d ys__n%d\n", si.in1, si.in2, si.id);
 			fprintf(f, "01 1\n");
 			fprintf(f, "10 1\n");
 		} else if (si.type == G(XNOR)) {
-			fprintf(f, ".names n%d n%d n%d\n", si.in1, si.in2, si.id);
+			fprintf(f, ".names ys__n%d ys__n%d ys__n%d\n", si.in1, si.in2, si.id);
 			fprintf(f, "00 1\n");
 			fprintf(f, "11 1\n");
 		} else if (si.type == G(ANDNOT)) {
-			fprintf(f, ".names n%d n%d n%d\n", si.in1, si.in2, si.id);
+			fprintf(f, ".names ys__n%d ys__n%d ys__n%d\n", si.in1, si.in2, si.id);
 			fprintf(f, "10 1\n");
 		} else if (si.type == G(ORNOT)) {
-			fprintf(f, ".names n%d n%d n%d\n", si.in1, si.in2, si.id);
+			fprintf(f, ".names ys__n%d ys__n%d ys__n%d\n", si.in1, si.in2, si.id);
 			fprintf(f, "1- 1\n");
 			fprintf(f, "-0 1\n");
 		} else if (si.type == G(MUX)) {
-			fprintf(f, ".names n%d n%d n%d n%d\n", si.in1, si.in2, si.in3, si.id);
+			fprintf(f, ".names ys__n%d ys__n%d ys__n%d ys__n%d\n", si.in1, si.in2, si.in3, si.id);
 			fprintf(f, "1-0 1\n");
 			fprintf(f, "-11 1\n");
 		} else if (si.type == G(AOI3)) {
-			fprintf(f, ".names n%d n%d n%d n%d\n", si.in1, si.in2, si.in3, si.id);
+			fprintf(f, ".names ys__n%d ys__n%d ys__n%d ys__n%d\n", si.in1, si.in2, si.in3, si.id);
 			fprintf(f, "-00 1\n");
 			fprintf(f, "0-0 1\n");
 		} else if (si.type == G(OAI3)) {
-			fprintf(f, ".names n%d n%d n%d n%d\n", si.in1, si.in2, si.in3, si.id);
+			fprintf(f, ".names ys__n%d ys__n%d ys__n%d ys__n%d\n", si.in1, si.in2, si.in3, si.id);
 			fprintf(f, "00- 1\n");
 			fprintf(f, "--0 1\n");
 		} else if (si.type == G(AOI4)) {
-			fprintf(f, ".names n%d n%d n%d n%d n%d\n", si.in1, si.in2, si.in3, si.in4, si.id);
+			fprintf(f, ".names ys__n%d ys__n%d ys__n%d ys__n%d ys__n%d\n", si.in1, si.in2, si.in3, si.in4, si.id);
 			fprintf(f, "-0-0 1\n");
 			fprintf(f, "-00- 1\n");
 			fprintf(f, "0--0 1\n");
 			fprintf(f, "0-0- 1\n");
 		} else if (si.type == G(OAI4)) {
-			fprintf(f, ".names n%d n%d n%d n%d n%d\n", si.in1, si.in2, si.in3, si.in4, si.id);
+			fprintf(f, ".names ys__n%d ys__n%d ys__n%d ys__n%d ys__n%d\n", si.in1, si.in2, si.in3, si.in4, si.id);
 			fprintf(f, "00-- 1\n");
 			fprintf(f, "--00 1\n");
 		} else if (si.type == G(FF)) {
 			if (si.init == State::S0 || si.init == State::S1) {
-				fprintf(f, ".latch n%d n%d %d\n", si.in1, si.id, si.init == State::S1 ? 1 : 0);
+				fprintf(f, ".latch ys__n%d ys__n%d %d\n", si.in1, si.id, si.init == State::S1 ? 1 : 0);
 				recover_init = true;
 			} else
-				fprintf(f, ".latch n%d n%d 2\n", si.in1, si.id);
+				fprintf(f, ".latch ys__n%d ys__n%d 2\n", si.in1, si.id);
 		} else if (si.type != G(NONE))
 			log_abort();
 		if (si.type != G(NONE))
@@ -889,7 +908,6 @@ void abc_module(RTLIL::Design *design, RTLIL::Module *current_module, std::strin
 	log("Extracted %d gates and %d wires to a netlist network with %d inputs and %d outputs.\n",
 			count_gates, GetSize(signal_list), count_input, count_output);
 	log_push();
-
 	if (count_output > 0)
 	{
 		log_header(design, "Executing ABC.\n");
@@ -988,7 +1006,10 @@ void abc_module(RTLIL::Design *design, RTLIL::Module *current_module, std::strin
 			log_error("ABC output file does not contain a module `netlist'.\n");
 		for (auto &it : mapped_mod->wires_) {
 			RTLIL::Wire *w = it.second;
-			RTLIL::Wire *wire = module->addWire(remap_name(w->name));
+			RTLIL::Wire *orig_wire = nullptr;
+			RTLIL::Wire *wire = module->addWire(remap_name(w->name, &orig_wire));
+			if (orig_wire != nullptr && orig_wire->attributes.count("\\src"))
+				wire->attributes["\\src"] = orig_wire->attributes["\\src"];
 			if (markgroups) wire->attributes["\\abcgroup"] = map_autoidx;
 			design->select(module, wire);
 		}
@@ -1213,7 +1234,7 @@ void abc_module(RTLIL::Design *design, RTLIL::Module *current_module, std::strin
 		for (auto &si : signal_list)
 			if (si.is_port) {
 				char buffer[100];
-				snprintf(buffer, 100, "\\n%d", si.id);
+				snprintf(buffer, 100, "\\ys__n%d", si.id);
 				RTLIL::SigSig conn;
 				if (si.type != G(NONE)) {
 					conn.first = si.bit;
@@ -1407,6 +1428,11 @@ struct AbcPass : public Pass {
 		log("        this attribute is a unique integer for each ABC process started. This\n");
 		log("        is useful for debugging the partitioning of clock domains.\n");
 		log("\n");
+		log("    -dress\n");
+		log("        run the 'dress' command after all other ABC commands. This aims to\n");
+		log("        preserve naming by an equivalence check between the original and post-ABC\n");
+		log("        netlists (experimental).\n");
+		log("\n");
 		log("When neither -liberty nor -lut is used, the Yosys standard cell library is\n");
 		log("loaded into ABC before the ABC script is executed.\n");
 		log("\n");
@@ -1441,6 +1467,7 @@ struct AbcPass : public Pass {
 		std::string delay_target, sop_inputs, sop_products, lutin_shared = "-S 1";
 		bool fast_mode = false, dff_mode = false, keepff = false, cleanup = true;
 		bool show_tempdir = false, sop_mode = false;
+		bool abc_dress = false;
 		vector<int> lut_costs;
 		markgroups = false;
 
@@ -1555,6 +1582,10 @@ struct AbcPass : public Pass {
 				map_mux16 = true;
 				continue;
 			}
+			if (arg == "-dress") {
+				abc_dress = true;
+				continue;
+			}
 			if (arg == "-g" && argidx+1 < args.size()) {
 				for (auto g : split_tokens(args[++argidx], ",")) {
 					vector<string> gate_list;
@@ -1704,7 +1735,7 @@ struct AbcPass : public Pass {
 
 			if (!dff_mode || !clk_str.empty()) {
 				abc_module(design, mod, script_file, exe_file, liberty_file, constr_file, cleanup, lut_costs, dff_mode, clk_str, keepff,
-						delay_target, sop_inputs, sop_products, lutin_shared, fast_mode, mod->selected_cells(), show_tempdir, sop_mode);
+						delay_target, sop_inputs, sop_products, lutin_shared, fast_mode, mod->selected_cells(), show_tempdir, sop_mode, abc_dress);
 				continue;
 			}
 
@@ -1849,7 +1880,7 @@ struct AbcPass : public Pass {
 				en_polarity = std::get<2>(it.first);
 				en_sig = assign_map(std::get<3>(it.first));
 				abc_module(design, mod, script_file, exe_file, liberty_file, constr_file, cleanup, lut_costs, !clk_sig.empty(), "$",
-						keepff, delay_target, sop_inputs, sop_products, lutin_shared, fast_mode, it.second, show_tempdir, sop_mode);
+						keepff, delay_target, sop_inputs, sop_products, lutin_shared, fast_mode, it.second, show_tempdir, sop_mode, abc_dress);
 				assign_map.set(mod);
 			}
 		}