From df4b405f9c1cd3ebfd2787b5f1f6925cabf789d3 Mon Sep 17 00:00:00 2001
From: Yoichi Hirai <i@yoichihirai.com>
Date: Mon, 24 Oct 2016 17:33:57 +0200
Subject: [PATCH] Add more optimization rules

---
 libevmasm/ExpressionClasses.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libevmasm/ExpressionClasses.cpp b/libevmasm/ExpressionClasses.cpp
index bb71be2e7..d5ccd7e3c 100644
--- a/libevmasm/ExpressionClasses.cpp
+++ b/libevmasm/ExpressionClasses.cpp
@@ -255,6 +255,7 @@ Rules::Rules()
 		{{Instruction::AND, {X, 0}}, [=]{ return u256(0); }},
 		{{Instruction::MUL, {X, 0}}, [=]{ return u256(0); }},
 		{{Instruction::DIV, {X, 0}}, [=]{ return u256(0); }},
+		{{Instruction::DIV, {0, X}}, [=]{ return u256(0); }},
 		{{Instruction::MOD, {X, 0}}, [=]{ return u256(0); }},
 		{{Instruction::MOD, {0, X}}, [=]{ return u256(0); }},
 		{{Instruction::OR, {X, ~u256(0)}}, [=]{ return ~u256(0); }},
@@ -272,6 +273,11 @@ Rules::Rules()
 		{{Instruction::MOD, {X, X}}, [=]{ return u256(0); }},
 
 		{{Instruction::NOT, {{Instruction::NOT, {X}}}}, [=]{ return X; }},
+		{{Instruction::XOR, {{{X}, {Instruction::XOR, {X, Y}}}}}, [=]{ return Y; }},
+		{{Instruction::OR, {{{X}, {Instruction::AND, {X, Y}}}}}, [=]{ return X; }},
+		{{Instruction::AND, {{{X}, {Instruction::OR, {X, Y}}}}}, [=]{ return X; }},
+		{{Instruction::AND, {{{X}, {Instruction::NOT, {X}}}}}, [=]{ return u256(0); }},
+		{{Instruction::OR, {{{X}, {Instruction::NOT, {X}}}}}, [=]{ return ~u256(0); }},
 	};
 	// Double negation of opcodes with binary result
 	for (auto const& op: vector<Instruction>{