diff --git a/passes/opt/Makefile.inc b/passes/opt/Makefile.inc
index c388bb8da..96566c588 100644
--- a/passes/opt/Makefile.inc
+++ b/passes/opt/Makefile.inc
@@ -33,6 +33,7 @@ PEEPOPT_PATTERN += passes/opt/peepopt_shiftmul_left.pmg
 PEEPOPT_PATTERN += passes/opt/peepopt_shiftadd.pmg
 PEEPOPT_PATTERN += passes/opt/peepopt_muldiv.pmg
 PEEPOPT_PATTERN += passes/opt/peepopt_muldiv_c.pmg
+PEEPOPT_PATTERN += passes/opt/peepopt_addsub_c.pmg
 PEEPOPT_PATTERN += passes/opt/peepopt_muxorder.pmg
 PEEPOPT_PATTERN += passes/opt/peepopt_formal_clockgateff.pmg
 PEEPOPT_PATTERN += passes/opt/peepopt_sub_neg.pmg
diff --git a/passes/opt/peepopt.cc b/passes/opt/peepopt.cc
index c2597cbfc..1ef160191 100644
--- a/passes/opt/peepopt.cc
+++ b/passes/opt/peepopt.cc
@@ -51,6 +51,8 @@ struct PeepoptPass : public Pass {
 		log("\n");
 		log("This pass employs the following rules by default:\n");
 		log("\n");
+		log("   * addsub_c - Replace (A+-B)+-C with A+(B+-C) when B and C are constants.\n");
+		log("\n");
 		log("   * muldiv - Replace (A*B)/B with A\n");
 		log("\n");
 		log("   * muldiv_c - Replace (A*B)/C with A*(B/C) when C is a const divisible by B.\n");
@@ -127,6 +129,7 @@ struct PeepoptPass : public Pass {
 					pm.run_shiftmul_left();
 					pm.run_muldiv();
 					pm.run_muldiv_c();
+					pm.run_addsub_c();
 					pm.run_sub_neg();
 					if (muxorder)
 						pm.run_muxorder();
diff --git a/passes/opt/peepopt_addsub_c.pmg b/passes/opt/peepopt_addsub_c.pmg
new file mode 100644
index 000000000..9002d55b7
--- /dev/null
+++ b/passes/opt/peepopt_addsub_c.pmg
@@ -0,0 +1,101 @@
+pattern addsub_c
+//
+// Authored by Akash Levy of Silimate, Inc. under ISC license.
+// Transforms add->add/sub_c into add_c folding the constants:
+// y = (a +- b_const) +- c_const   ===>   a +- eval(b_const +- c_const)
+//
+
+state <SigSpec> a b_const addsub1_y
+
+match addsub1
+	// Select add/sub
+	select addsub1->type.in($add, $sub)
+endmatch
+
+code a b_const addsub1_y
+	// Get adder signals
+	a = port(addsub1, \A);
+	b_const = port(addsub1, \B);
+	addsub1_y = port(addsub1, \Y);
+
+	// A and B can be interchanged for adder
+	if (addsub1->type == $add) {
+		branch;
+		std::swap(a, b_const);
+	}
+endcode
+
+match addsub2
+	// Select add/sub of form (a +- b_const) +- c_const
+	select addsub2->type.in($add, $sub)
+
+	// Check that b_const and c_const is constant
+	filter b_const.is_fully_const()
+	filter port(addsub2, \B).is_fully_const()
+	index <SigSpec> port(addsub2, \A) === addsub1_y
+endmatch
+
+code
+	// New addsub1 cell (will be reused unless there is external fanout)
+	auto cell = addsub1;
+
+	// Get addsub2 signals
+	SigSpec c_const = port(addsub2, \B);
+	SigSpec addsub2_y = port(addsub2, \Y);
+
+	// Get properties and values of b_const and c_const
+	// b_const may be coming from the A port
+	// But it is an RTLIL invariant that A_SIGNED equals B_SIGNED
+	bool b_const_signed = addsub1->getParam(ID::B_SIGNED).as_bool();
+	bool c_const_signed = addsub2->getParam(ID::B_SIGNED).as_bool();
+	int b_const_int = b_const.as_int(b_const_signed);
+	int c_const_int = c_const.as_int(c_const_signed);
+
+	// Calculate the constant and compress the width to fit the value
+	Const const_value;
+	if (addsub1->type == $add)
+		if (addsub2->type == $add)
+			const_value = b_const_int + c_const_int;
+		else
+			const_value = b_const_int - c_const_int;
+	else
+		if (addsub2->type == $add)
+			const_value = b_const_int - c_const_int;
+		else
+			const_value = b_const_int + c_const_int;
+	const_value.compress(b_const_signed | c_const_signed);
+
+	// Integer values should be lesser than 32 bits
+	// This is because we are using C++ types, and int is 32 bits
+	// FIXME: use long long or BigInteger to make pass work with >32 bits
+	if (addsub1->getParam(ID::A_WIDTH).as_int() > 32)
+		reject;
+	if (addsub1->getParam(ID::B_WIDTH).as_int() > 32)
+		reject;
+	if (addsub2->getParam(ID::A_WIDTH).as_int() > 32)
+		reject;
+	if (addsub2->getParam(ID::B_WIDTH).as_int() > 32)
+		reject;
+	if (GetSize(b_const) > 32)
+		reject;
+	if (GetSize(c_const) > 32)
+		reject;
+
+	// Reuse/create new cell to drive the folded expression
+	if (nusers(addsub1_y) != 2) {
+		cell = module->addCell(NEW_ID2_SUFFIX("asconst"), addsub1->type);
+		cell->attributes = addsub1->attributes;
+		cell->parameters = addsub1->parameters;
+	}
+	cell->setPort(\A, a);
+	cell->setPort(\B, const_value);
+	cell->setPort(\Y, addsub2_y);
+
+	// Remove addsub2
+	autoremove(addsub2);
+
+	// Log, fixup, accept
+	log("addsub_const pattern in %s: addsub1=%s, addsub2=%s\n", log_id(module), log_id(addsub1), log_id(addsub2));
+	cell->fixup_parameters();
+	accept;
+endcode
diff --git a/tests/peepopt/addsub_c.ys b/tests/peepopt/addsub_c.ys
new file mode 100644
index 000000000..6a3888542
--- /dev/null
+++ b/tests/peepopt/addsub_c.ys
@@ -0,0 +1,953 @@
+log -header "Test simple positive case 1"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [31:0] a,
+  output wire  [31:0] y
+);
+  assign y = a + 1023 + 127;
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+design -reset
+log -pop
+
+log -header "Test simple positive case 2"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [31:0] a,
+  output wire  [31:0] y
+);
+  assign y = a + 1023 - 127;
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+design -reset
+log -pop
+
+log -header "Test simple positive case 3"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [31:0] a,
+  output wire  [31:0] y
+);
+  assign y = a - 1023 + 127;
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 0
+select t:$sub -assert-count 1
+design -reset
+log -pop
+
+log -header "Test simple positive case 4"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [31:0] a,
+  output wire  [31:0] y
+);
+  assign y = a - 1023 - 127;
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 0
+select t:$sub -assert-count 1
+design -reset
+log -pop
+
+
+
+log -header "Signed pattern transformed: (a +- b) +- c case 1"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y
+);
+	wire signed [7:0] add;
+	assign add = a + 4'sd6;
+	assign y = add + 8'sd3;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 1 t:$add
+select -assert-count 0 t:$sub
+design -reset
+log -pop
+
+log -header "Signed pattern transformed: (a +- b) +- c case 2"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y
+);
+	wire signed [7:0] add;
+	assign add = a + 4'sd6;
+	assign y = add - 8'sd3;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 1 t:$add
+select -assert-count 0 t:$sub
+design -reset
+log -pop
+
+log -header "Signed pattern transformed: (a +- b) +- c case 3"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y
+);
+	wire signed [7:0] sub;
+	assign sub = a - 4'sd6;
+	assign y = sub + 8'sd3;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 0 t:$add
+select -assert-count 1 t:$sub
+design -reset
+log -pop
+
+log -header "Signed pattern transformed: (a +- b) +- c case 4"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y
+);
+	wire signed [7:0] sub;
+	assign sub = a - 4'sd6;
+	assign y = sub - 8'sd3;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 0 t:$add
+select -assert-count 1 t:$sub
+design -reset
+log -pop
+
+
+
+log -header "Symmetry case 1"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y
+);
+	wire signed [7:0] add;
+	assign add = 4'sd6 + a;
+	assign y = add + 8'sd3;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 1 t:$add
+select -assert-count 0 t:$sub
+design -reset
+log -pop
+
+log -header "Symmetry case 2"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y
+);
+	wire signed [7:0] add;
+	assign add = 4'sd6 + a;
+	assign y = add - 8'sd3;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 1 t:$add
+select -assert-count 0 t:$sub
+design -reset
+log -pop
+
+log -header "Symmetry case 3: no transformation since constant is first"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y
+);
+	wire signed [7:0] sub;
+	assign sub = 4'sd6 - a;
+	assign y = sub + 8'sd3;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 1 t:$add
+select -assert-count 1 t:$sub
+design -reset
+log -pop
+
+log -header "Symmetry case 4: no transformation since constant is first"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y
+);
+	wire signed [7:0] sub;
+	assign sub = 4'sd6 - a;
+	assign y = sub - 8'sd3;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 0 t:$add
+select -assert-count 2 t:$sub
+design -reset
+log -pop
+
+
+
+log -header "Transformed on b == c case 1"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y
+);
+	wire signed [7:0] add;
+	assign add = a + 4'sd6;
+	assign y = add + 8'sd6;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 1 t:$add
+select -assert-count 0 t:$sub
+design -reset
+log -pop
+
+log -header "Transformed on b == c case 2"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y
+);
+	wire signed [7:0] add;
+	assign add = a + 4'sd6;
+	assign y = add - 8'sd6;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 1 t:$add
+select -assert-count 0 t:$sub
+design -reset
+log -pop
+
+log -header "Transformed on b == c case 3"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y
+);
+	wire signed [7:0] sub;
+	assign sub = a - 4'sd6;
+	assign y = sub + 8'sd6;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 0 t:$add
+select -assert-count 1 t:$sub
+design -reset
+log -pop
+
+log -header "Transformed on b == c case 4"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y
+);
+	wire signed [7:0] sub;
+	assign sub = a - 4'sd6;
+	assign y = sub - 8'sd6;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 0 t:$add
+select -assert-count 1 t:$sub
+design -reset
+log -pop
+
+
+
+log -header "b negative, c positive case 1"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y
+);
+	wire signed [7:0] add;
+	assign add = a + (-4'sd6);
+	assign y = add + 8'sd3;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 1 t:$add
+select -assert-count 0 t:$sub
+design -reset
+log -pop
+
+log -header "b negative, c positive case 2"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y
+);
+	wire signed [7:0] add;
+	assign add = a + (-4'sd6);
+	assign y = add - 8'sd3;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 1 t:$add
+select -assert-count 0 t:$sub
+design -reset
+log -pop
+
+log -header "b negative, c positive case 3"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y
+);
+	wire signed [7:0] sub;
+	assign sub = a - (-4'sd6);
+	assign y = sub + 8'sd3;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 0 t:$add
+select -assert-count 1 t:$sub
+design -reset
+log -pop
+
+log -header "b negative, c positive case 4"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y
+);
+	wire signed [7:0] sub;
+	assign sub = a - (-4'sd6);
+	assign y = sub - 8'sd3;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 0 t:$add
+select -assert-count 1 t:$sub
+design -reset
+log -pop
+
+
+
+log -header "Transform even when addsub1 has a second fanout case 1"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y,
+	output signed [7:0] z
+);
+	wire signed [7:0] add;
+	assign add = a + 4'sd6;
+	assign y = add + 8'sd3;
+	assign z = add;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 2 t:$add
+select -assert-count 0 t:$sub
+design -reset
+log -pop
+
+log -header "Transform even when addsub1 has a second fanout case 2"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y,
+	output signed [7:0] z
+);
+	wire signed [7:0] add;
+	assign add = a + 4'sd6;
+	assign y = add - 8'sd3;
+	assign z = add;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 2 t:$add
+select -assert-count 0 t:$sub
+design -reset
+log -pop
+
+log -header "Transform even when addsub1 has a second fanout case 3"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y,
+	output signed [7:0] z
+);
+	wire signed [7:0] sub;
+	assign sub = a - 4'sd6;
+	assign y = sub + 8'sd3;
+	assign z = sub;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 0 t:$add
+select -assert-count 2 t:$sub
+design -reset
+log -pop
+
+log -header "Transform even when addsub1 has a second fanout case 4"
+log -push
+read_verilog <<EOT
+module top(
+	input signed [3:0] a,
+	output signed [7:0] y,
+	output signed [7:0] z
+);
+	wire signed [7:0] sub;
+	assign sub = a - 4'sd6;
+	assign y = sub - 8'sd3;
+	assign z = sub;
+endmodule
+EOT
+equiv_opt -assert peepopt
+design -load postopt
+select -assert-count 0 t:$add
+select -assert-count 2 t:$sub
+design -reset
+log -pop
+
+
+
+# =============================================================================
+# OVERFLOW TESTS
+# =============================================================================
+
+log -header "Overflow test: unsigned 4-bit max value + constant"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [3:0] a,
+  output wire  [7:0] y
+);
+  assign y = a + 4'd15 + 4'd1;  // 15 + 1 = 16 (overflows 4-bit but not 7-bit)
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+design -reset
+log -pop
+
+log -header "Overflow test: signed 4-bit max value + constant"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input signed [3:0] a,
+  output signed [7:0] y
+);
+  assign y = a + 4'sd7 + 4'sd1;  // 7 + 1 = 8 (overflows 4-bit signed but not 7-bit)
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+design -reset
+log -pop
+
+log -header "Overflow test: negative signed constants"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input signed [3:0] a,
+  output signed [7:0] y
+);
+  assign y = a + (-4'sd8) + (-4'sd1);  // -8 + (-1) = -9 (underflows 4-bit signed but not 7-bit)
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+design -reset
+log -pop
+
+log -header "Large constant test: 32-bit constants"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [31:0] a,
+  output wire  [31:0] y
+);
+  assign y = a + 32'h7FFFFFFF + 32'h1;  // Large positive constants
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+design -reset
+log -pop
+
+# =============================================================================
+# SIGNEDNESS MIXING TESTS
+# =============================================================================
+
+log -header "Mixed signedness: unsigned input with signed constants"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [7:0] a,
+  output signed [15:0] y
+);
+  wire signed [15:0] temp;
+  assign temp = a + 8'sd10;
+  assign y = temp + 16'sd5;
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+design -reset
+log -pop
+
+log -header "Mixed signedness: signed input with unsigned constants"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input signed [7:0] a,
+  output wire [15:0] y
+);
+  wire [15:0] temp;
+  assign temp = a + 8'd10;
+  assign y = temp + 16'd5;
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+design -reset
+log -pop
+
+# =============================================================================
+# DRIVING OTHER OPERATIONS TESTS
+# =============================================================================
+
+log -header "Result drives multiplication"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [7:0] a,
+  input wire  [7:0] b,
+  output wire  [15:0] y
+);
+  wire [7:0] temp;
+  assign temp = a + 8'd10 + 8'd5;
+  assign y = temp * b;
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+select t:$mul -assert-count 1
+design -reset
+log -pop
+
+log -header "Result drives comparison"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [7:0] a,
+  output wire  y
+);
+  wire [7:0] temp;
+  assign temp = a + 8'd10 + 8'd5;
+  assign y = temp > 8'd100;
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+select t:$gt -assert-count 1
+design -reset
+log -pop
+
+log -header "Result drives logical operations"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [7:0] a,
+  input wire  [7:0] b,
+  output wire  [7:0] y
+);
+  wire [7:0] temp;
+  assign temp = a + 8'd10 + 8'd5;
+  assign y = temp & b;
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+select t:$and -assert-count 1
+design -reset
+log -pop
+
+log -header "Result drives shift operation"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [7:0] a,
+  output wire  [7:0] y
+);
+  wire [7:0] temp;
+  assign temp = a + 8'd10 + 8'd5;
+  assign y = temp << 2;
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+select t:$shl -assert-count 1
+design -reset
+log -pop
+
+# =============================================================================
+# WEIRD STRUCTURES AND EDGE CASES
+# =============================================================================
+
+log -header "Zero constant optimization"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [7:0] a,
+  output wire  [7:0] y
+);
+  assign y = a + 8'd10 + 8'd0;  // Should optimize to just a + 10
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+design -reset
+log -pop
+
+log -header "Constants that cancel out"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [7:0] a,
+  output wire  [7:0] y
+);
+  assign y = a + 8'd10 - 8'd10;  // Should optimize to just a
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+# After optimization, this should either be no operations or just a wire connection
+design -reset
+log -pop
+
+log -header "Triple chained operations (optimizes fully)"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [7:0] a,
+  output wire  [7:0] y
+);
+  wire [7:0] temp1, temp2;
+  assign temp1 = a + 8'd5;
+  assign temp2 = temp1 + 8'd10;
+  assign y = temp2 + 8'd3;
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+# The optimization actually works on multiple levels
+select t:$add -assert-count 1  # Optimizes to single add (a + 18)
+select t:$sub -assert-count 0
+design -reset
+log -pop
+
+log -header "Different bit widths in chain"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [4:0] a,
+  output wire  [15:0] y
+);
+  wire [10:0] temp;
+  assign temp = a + 5'd10;
+  assign y = temp + 11'd500;
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+design -reset
+log -pop
+
+log -header "Negative result from subtraction chain"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input signed [7:0] a,
+  output signed [7:0] y
+);
+  assign y = a - 8'sd100 - 8'sd50;  // Should result in a - 150
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 0
+select t:$sub -assert-count 1
+design -reset
+log -pop
+
+log -header "Mixed add/sub with large intermediate result"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [7:0] a,
+  output wire  [15:0] y
+);
+  wire [15:0] temp;
+  assign temp = a + 8'd255;
+  assign y = temp - 16'd100;
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+design -reset
+log -pop
+
+log -header "Single bit operations"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  a,
+  output wire  [7:0] y
+);
+  wire [7:0] temp;
+  assign temp = a + 1'd1;
+  assign y = temp + 8'd5;
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+design -reset
+log -pop
+
+log -header "Constants with different representations (hex, decimal, binary)"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [7:0] a,
+  output wire  [7:0] y
+);
+  assign y = a + 8'hFF + 8'b00000001;  // 255 + 1 = 256 (overflows to 0 in 8-bit)
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+design -reset
+log -pop
+
+# =============================================================================
+# CORNER CASES FOR PATTERN MATCHING
+# =============================================================================
+
+log -header "Constants in A position (commutative add)"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [7:0] a,
+  output wire  [7:0] y
+);
+  wire [7:0] temp;
+  assign temp = 8'd10 + a;  // Constant first
+  assign y = temp + 8'd5;
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+design -reset
+log -pop
+
+log -header "Very small bit widths"
+log -push
+design -reset
+read_verilog <<EOF
+module top (
+  input wire  [1:0] a,
+  output wire  [3:0] y
+);
+  wire [3:0] temp;
+  assign temp = a + 2'd1;
+  assign y = temp + 4'd2;
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+design -reset
+log -pop
+
+log -header "Test with parameters/generics"
+log -push
+design -reset
+read_verilog <<EOF
+module top #(parameter WIDTH = 8) (
+  input wire  [WIDTH-1:0] a,
+  output wire  [WIDTH+2:0] y
+);
+  wire [WIDTH+2:0] temp;
+  assign temp = a + 5;
+  assign y = temp + 3;
+endmodule
+EOF
+check -assert
+wreduce
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 1
+select t:$sub -assert-count 0
+design -reset
+log -pop
+
+log -header "Final test case"
+log -push
+design -reset
+read_verilog -sv <<EOF
+module top (
+	input logic [7:0] var_exp_a,
+	input logic var_zero_a,
+	input logic var_inf_a,
+	output logic var_zero_ac,
+	output logic var_inf_ac,
+	output logic signed [11:0] var_exp_ac
+);
+  assign var_exp_ac = $signed({1'b0, var_exp_a}) - 1023 + 127;
+	assign var_zero_ac = var_zero_a | (var_exp_ac <= 0);
+	assign var_inf_ac = var_inf_a | (var_exp_ac >= 255);
+endmodule
+EOF
+check -assert
+equiv_opt -assert peepopt
+design -load postopt
+select t:$add -assert-count 0
+select t:$sub -assert-count 1
+design -reset
+log -pop