From a0e99a9f3f0a52e3a6f2000791d93b54ce116928 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Marcelina=20Ko=C5=9Bcielnicka?= <mwk@0x04.net>
Date: Wed, 15 Jul 2020 02:37:43 +0200
Subject: [PATCH] peepopt: Remove now-redundant dffmux pattern.

---
 passes/pmgen/Makefile.inc       |   1 -
 passes/pmgen/peepopt.cc         |   3 -
 passes/pmgen/peepopt_dffmux.pmg | 171 --------------------------------
 tests/opt/opt_dff_dffmux.ys     | 129 ++++++++++++++++++++++++
 tests/various/peepopt.ys        | 143 --------------------------
 5 files changed, 129 insertions(+), 318 deletions(-)
 delete mode 100644 passes/pmgen/peepopt_dffmux.pmg
 create mode 100644 tests/opt/opt_dff_dffmux.ys

diff --git a/passes/pmgen/Makefile.inc b/passes/pmgen/Makefile.inc
index 1a57bef7d..c6bbc386a 100644
--- a/passes/pmgen/Makefile.inc
+++ b/passes/pmgen/Makefile.inc
@@ -36,7 +36,6 @@ $(eval $(call add_extra_objs,passes/pmgen/peepopt_pm.h))
 
 PEEPOPT_PATTERN  = passes/pmgen/peepopt_shiftmul.pmg
 PEEPOPT_PATTERN += passes/pmgen/peepopt_muldiv.pmg
-PEEPOPT_PATTERN += passes/pmgen/peepopt_dffmux.pmg
 
 passes/pmgen/peepopt_pm.h: passes/pmgen/pmgen.py $(PEEPOPT_PATTERN)
 	$(P) mkdir -p passes/pmgen && $(PYTHON_EXECUTABLE) $< -o $@ -p peepopt $(filter-out $<,$^)
diff --git a/passes/pmgen/peepopt.cc b/passes/pmgen/peepopt.cc
index c16b4486d..a9c62fcf6 100644
--- a/passes/pmgen/peepopt.cc
+++ b/passes/pmgen/peepopt.cc
@@ -67,8 +67,6 @@ struct PeepoptPass : public Pass {
 				GENERATE_PATTERN(peepopt_pm, shiftmul);
 			else if (genmode == "muldiv")
 				GENERATE_PATTERN(peepopt_pm, muldiv);
-			else if (genmode == "dffmux")
-				GENERATE_PATTERN(peepopt_pm, dffmux);
 			else
 				log_abort();
 			return;
@@ -106,7 +104,6 @@ struct PeepoptPass : public Pass {
 
 				pm.run_shiftmul();
 				pm.run_muldiv();
-				pm.run_dffmux();
 
 				for (auto w : module->wires()) {
 					auto it = w->attributes.find(ID::init);
diff --git a/passes/pmgen/peepopt_dffmux.pmg b/passes/pmgen/peepopt_dffmux.pmg
deleted file mode 100644
index 0069b0570..000000000
--- a/passes/pmgen/peepopt_dffmux.pmg
+++ /dev/null
@@ -1,171 +0,0 @@
-pattern dffmux
-
-state <IdString> cemuxAB rstmuxBA
-state <SigSpec> sigD
-
-match dff
-	select dff->type == $dff
-	select GetSize(port(dff, \D)) > 1
-endmatch
-
-code sigD
-	sigD = port(dff, \D);
-endcode
-
-match rstmux
-	select rstmux->type == $mux
-	select GetSize(port(rstmux, \Y)) > 1
-	index <SigSpec> port(rstmux, \Y) === sigD
-	choice <IdString> BA {\B, \A}
-	select port(rstmux, BA).is_fully_const()
-	set rstmuxBA BA
-	semioptional
-endmatch
-
-code sigD
-	if (rstmux)
-		sigD = port(rstmux, rstmuxBA == \B ? \A : \B);
-endcode
-
-match cemux
-	select cemux->type == $mux
-	select GetSize(port(cemux, \Y)) > 1
-	index <SigSpec> port(cemux, \Y) === sigD
-	choice <IdString> AB {\A, \B}
-	index <SigSpec> port(cemux, AB) === port(dff, \Q)
-	set cemuxAB AB
-	semioptional
-endmatch
-
-code
-	if (!cemux && !rstmux)
-		reject;
-endcode
-
-code
-	Const rst;
-	SigSpec D;
-	if (cemux) {
-		D = port(cemux, cemuxAB == \A ? \B : \A);
-		if (rstmux)
-			rst = port(rstmux, rstmuxBA).as_const();
-		else
-			rst = Const(State::Sx, GetSize(D));
-	}
-	else {
-		log_assert(rstmux);
-		D = port(rstmux, rstmuxBA  == \B ? \A : \B);
-		rst = port(rstmux, rstmuxBA).as_const();
-	}
-	SigSpec Q = port(dff, \Q);
-	int width = GetSize(D);
-
-	SigSpec dffD = dff->getPort(\D);
-	SigSpec dffQ = dff->getPort(\Q);
-
-	Const initval;
-	for (auto b : Q) {
-		auto it = initbits.find(b);
-		initval.bits.push_back(it == initbits.end() ? State::Sx : it->second);
-	}
-
-	auto cmpx = [=](State lhs, State rhs) {
-		if (lhs == State::Sx || rhs == State::Sx)
-			return true;
-		return lhs == rhs;
-	};
-
-	int i = width-1;
-	while (i > 1) {
-		if (D[i] != D[i-1])
-			break;
-		if (!cmpx(rst[i], rst[i-1]))
-			break;
-		if (!cmpx(initval[i], initval[i-1]))
-			break;
-		if (!cmpx(rst[i], initval[i]))
-			break;
-		rminitbits.insert(Q[i]);
-		module->connect(Q[i], Q[i-1]);
-		i--;
-	}
-	if (i < width-1) {
-		did_something = true;
-		if (cemux) {
-			SigSpec ceA = cemux->getPort(\A);
-			SigSpec ceB = cemux->getPort(\B);
-			SigSpec ceY = cemux->getPort(\Y);
-			ceA.remove(i, width-1-i);
-			ceB.remove(i, width-1-i);
-			ceY.remove(i, width-1-i);
-			cemux->setPort(\A, ceA);
-			cemux->setPort(\B, ceB);
-			cemux->setPort(\Y, ceY);
-			cemux->fixup_parameters();
-			blacklist(cemux);
-		}
-		if (rstmux) {
-			SigSpec rstA = rstmux->getPort(\A);
-			SigSpec rstB = rstmux->getPort(\B);
-			SigSpec rstY = rstmux->getPort(\Y);
-			rstA.remove(i, width-1-i);
-			rstB.remove(i, width-1-i);
-			rstY.remove(i, width-1-i);
-			rstmux->setPort(\A, rstA);
-			rstmux->setPort(\B, rstB);
-			rstmux->setPort(\Y, rstY);
-			rstmux->fixup_parameters();
-			blacklist(rstmux);
-		}
-		dffD.remove(i, width-1-i);
-		dffQ.remove(i, width-1-i);
-		dff->setPort(\D, dffD);
-		dff->setPort(\Q, dffQ);
-		dff->fixup_parameters();
-		blacklist(dff);
-
-		log("dffcemux pattern in %s: dff=%s, cemux=%s, rstmux=%s; removed top %d bits.\n", log_id(module), log_id(dff), log_id(cemux, "n/a"), log_id(rstmux, "n/a"), width-1-i);
-		width = i+1;
-	}
-	if (cemux) {
-		SigSpec ceA = cemux->getPort(\A);
-		SigSpec ceB = cemux->getPort(\B);
-		SigSpec ceY = cemux->getPort(\Y);
-
-		int count = 0;
-		for (int i = width-1; i >= 0; i--) {
-			if (D[i].wire)
-				continue;
-			if (cmpx(rst[i], D[i].data) && cmpx(initval[i], D[i].data)) {
-				count++;
-				rminitbits.insert(Q[i]);
-				module->connect(Q[i], D[i]);
-				ceA.remove(i);
-				ceB.remove(i);
-				ceY.remove(i);
-				dffD.remove(i);
-				dffQ.remove(i);
-			}
-		}
-		if (count > 0)
-		{
-			did_something = true;
-
-			cemux->setPort(\A, ceA);
-			cemux->setPort(\B, ceB);
-			cemux->setPort(\Y, ceY);
-			cemux->fixup_parameters();
-			blacklist(cemux);
-
-			dff->setPort(\D, dffD);
-			dff->setPort(\Q, dffQ);
-			dff->fixup_parameters();
-			blacklist(dff);
-
-			log("dffcemux pattern in %s: dff=%s, cemux=%s, rstmux=%s; removed %d constant bits.\n", log_id(module), log_id(dff), log_id(cemux), log_id(rstmux, "n/a"), count);
-		}
-	}
-
-	if (did_something)
-		accept;
-endcode
diff --git a/tests/opt/opt_dff_dffmux.ys b/tests/opt/opt_dff_dffmux.ys
new file mode 100644
index 000000000..43190cc31
--- /dev/null
+++ b/tests/opt/opt_dff_dffmux.ys
@@ -0,0 +1,129 @@
+design -reset
+read_verilog <<EOT
+module opt_dffmuxext_unsigned(input clk, ce, input [1:0] i, output reg [3:0] o);
+    always @(posedge clk) if (ce) o <= i;
+endmodule
+EOT
+
+proc
+equiv_opt -assert opt
+design -load postopt
+select -assert-count 1 t:$dffe r:WIDTH=2 %i
+select -assert-count 0 t:$dffe %% t:* %D
+
+####################
+
+design -reset
+read_verilog <<EOT
+module opt_dffmuxext_signed(input clk, ce, input signed [1:0] i, output reg signed [3:0] o);
+    always @(posedge clk) if (ce) o <= i;
+endmodule
+EOT
+
+proc
+equiv_opt -assert opt
+design -load postopt
+wreduce
+select -assert-count 1 t:$dffe r:WIDTH=2 %i
+select -assert-count 0 t:$dffe %% t:* %D
+
+###################
+
+design -reset
+read_verilog <<EOT
+module opt_dffmuxext_const(input clk, ce, input [1:0] i, output reg [5:0] o);
+    always @(posedge clk) if (ce) o <= {1'b0, i[1], 2'b1x, i[0], 1'bz};
+endmodule
+EOT
+
+proc
+equiv_opt -assert opt
+design -load postopt
+select -assert-count 1 t:$dffe r:WIDTH=2 %i
+select -assert-count 0 t:$dffe %% t:* %D
+
+###################
+
+design -reset
+read_verilog <<EOT
+module opt_dffmuxext_const_init(input clk, ce, input [1:0] i, (* init=6'b0x00x1 *) output reg [5:0] o);
+    always @(posedge clk) if (ce) o <= {1'b0, i[1], 2'b1x, i[0], 1'bz};
+endmodule
+EOT
+
+proc
+equiv_opt -assert opt
+design -load postopt
+select -assert-count 1 t:$dffe r:WIDTH=4 %i
+select -assert-count 0 t:$dffe %% t:* %D
+
+####################
+
+design -reset
+read_verilog <<EOT
+module opt_dffmuxext_unsigned_rst(input clk, ce, rst, input [1:0] i, output reg [3:0] o);
+    always @(posedge clk) if (rst) o <= 0; else if (ce) o <= i;
+endmodule
+EOT
+
+proc
+equiv_opt -assert opt
+design -load postopt
+wreduce
+select -assert-count 1 t:$sdffe r:WIDTH=2 %i
+select -assert-count 0 t:$sdffe %% t:* %D
+
+####################
+
+design -reset
+read_verilog <<EOT
+module opt_dffmuxext_signed_rst(input clk, ce, rstn, input signed [1:0] i, output reg signed [3:0] o);
+    always @(posedge clk) begin
+        if (ce) o <= i;
+        if (!rstn) o <= 4'b1111;
+    end
+endmodule
+EOT
+
+proc
+equiv_opt -assert opt
+design -load postopt
+wreduce
+select -assert-count 1 t:$sdffe r:WIDTH=2 %i
+select -assert-count 0 t:$sdffe %% t:* %D
+
+####################
+
+design -reset
+read_verilog <<EOT
+module opt_dffmuxext_signed_rst_init(input clk, ce, rstn, input signed [1:0] i, output reg signed [3:0] o);
+    initial o <= 4'b0010;
+    always @(posedge clk) begin
+        if (ce) o <= i;
+        if (!rstn) o <= 4'b1111;
+    end
+endmodule
+EOT
+
+proc
+# NB: equiv_opt uses equiv_induct which covers
+#     only the induction half of temporal induction
+#     --- missing the base-case half
+#     This makes it akin to `sat -tempinduct-inductonly`
+#     instead of `sat -tempinduct-baseonly` or
+#     `sat -tempinduct` which is necessary for this
+#     testcase
+#equiv_opt -assert opt
+
+design -save gold
+opt
+wreduce
+design -stash gate
+design -import gold -as gold
+design -import gate -as gate
+miter -equiv -flatten -make_assert -make_outputs gold gate miter
+sat -tempinduct -verify -prove-asserts -show-ports miter
+
+design -load gate
+select -assert-count 1 t:$sdffe r:WIDTH=3 %i
+select -assert-count 0 t:$sdffe %% t:* %D
diff --git a/tests/various/peepopt.ys b/tests/various/peepopt.ys
index ee5ad8a1a..45e936a21 100644
--- a/tests/various/peepopt.ys
+++ b/tests/various/peepopt.ys
@@ -68,146 +68,3 @@ equiv_opt -assert peepopt
 design -load postopt
 clean
 select -assert-count 0 t:*
-
-####################
-
-design -reset
-read_verilog <<EOT
-module peepopt_dffmuxext_unsigned(input clk, ce, input [1:0] i, output reg [3:0] o);
-    always @(posedge clk) if (ce) o <= i;
-endmodule
-EOT
-
-proc
-equiv_opt -assert peepopt
-design -load postopt
-clean
-select -assert-count 1 t:$dff r:WIDTH=2 %i
-select -assert-count 1 t:$mux r:WIDTH=2 %i
-select -assert-count 0 t:$dff t:$mux %% t:* %D
-
-####################
-
-design -reset
-read_verilog <<EOT
-module peepopt_dffmuxext_signed(input clk, ce, input signed [1:0] i, output reg signed [3:0] o);
-    always @(posedge clk) if (ce) o <= i;
-endmodule
-EOT
-
-proc
-equiv_opt -assert peepopt
-design -load postopt
-clean
-select -assert-count 1 t:$dff r:WIDTH=2 %i
-select -assert-count 1 t:$mux r:WIDTH=2 %i
-select -assert-count 0 t:$dff t:$mux %% t:* %D
-
-###################
-
-design -reset
-read_verilog <<EOT
-module peepopt_dffmuxext_const(input clk, ce, input [1:0] i, output reg [5:0] o);
-    always @(posedge clk) if (ce) o <= {1'b0, i[1], 2'b1x, i[0], 1'bz};
-endmodule
-EOT
-
-proc
-equiv_opt -assert peepopt
-design -load postopt
-select -assert-count 1 t:$dff r:WIDTH=2 %i
-select -assert-count 1 t:$mux r:WIDTH=2 %i
-select -assert-count 0 t:$dff t:$mux %% t:* %D
-
-###################
-
-design -reset
-read_verilog <<EOT
-module peepopt_dffmuxext_const_init(input clk, ce, input [1:0] i, (* init=6'b0x00x1 *) output reg [5:0] o);
-    always @(posedge clk) if (ce) o <= {1'b0, i[1], 2'b1x, i[0], 1'bz};
-endmodule
-EOT
-
-proc
-equiv_opt -assert peepopt
-design -load postopt
-select -assert-count 1 t:$dff r:WIDTH=4 %i
-select -assert-count 1 t:$mux r:WIDTH=4 %i
-select -assert-count 0 t:$dff t:$mux %% t:* %D
-
-####################
-
-design -reset
-read_verilog <<EOT
-module peepopt_dffmuxext_unsigned_rst(input clk, ce, rst, input [1:0] i, output reg [3:0] o);
-    always @(posedge clk) if (rst) o <= 0; else if (ce) o <= i;
-endmodule
-EOT
-
-proc
-equiv_opt -assert peepopt
-design -load postopt
-wreduce
-select -assert-count 1 t:$dff r:WIDTH=2 %i
-select -assert-count 2 t:$mux
-select -assert-count 2 t:$mux r:WIDTH=2 %i
-select -assert-count 0 t:$dff t:$mux %% t:* %D
-
-####################
-
-design -reset
-read_verilog <<EOT
-module peepopt_dffmuxext_signed_rst(input clk, ce, rstn, input signed [1:0] i, output reg signed [3:0] o);
-    always @(posedge clk) begin
-        if (ce) o <= i;
-        if (!rstn) o <= 4'b1111;
-    end
-endmodule
-EOT
-
-proc
-equiv_opt -assert peepopt
-design -load postopt
-wreduce
-select -assert-count 1 t:$dff r:WIDTH=2 %i
-select -assert-count 2 t:$mux
-select -assert-count 2 t:$mux r:WIDTH=2 %i
-select -assert-count 0 t:$logic_not t:$dff t:$mux %% t:* %D
-
-####################
-
-design -reset
-read_verilog <<EOT
-module peepopt_dffmuxext_signed_rst_init(input clk, ce, rstn, input signed [1:0] i, output reg signed [3:0] o);
-    initial o <= 4'b0010;
-    always @(posedge clk) begin
-        if (ce) o <= i;
-        if (!rstn) o <= 4'b1111;
-    end
-endmodule
-EOT
-
-proc
-# NB: equiv_opt uses equiv_induct which covers
-#     only the induction half of temporal induction
-#     --- missing the base-case half
-#     This makes it akin to `sat -tempinduct-inductonly`
-#     instead of `sat -tempinduct-baseonly` or
-#     `sat -tempinduct` which is necessary for this
-#     testcase
-#equiv_opt -assert peepopt
-
-design -save gold
-peepopt
-wreduce
-design -stash gate
-design -import gold -as gold
-design -import gate -as gate
-miter -equiv -flatten -make_assert -make_outputs gold gate miter
-sat -tempinduct -verify -prove-asserts -show-ports miter
-
-design -load gate
-select -assert-count 1 t:$dff r:WIDTH=4 %i
-select -assert-count 2 t:$mux
-select -assert-count 2 t:$mux r:WIDTH=4 %i
-select -assert-count 0 t:$logic_not t:$dff t:$mux %% t:* %D
-- 
2.30.2