From 38460d8b473052bd9d4871ed7f10e72f8fb65615 Mon Sep 17 00:00:00 2001
From: Alex Beregszaszi <alex@rtfs.hu>
Date: Wed, 18 Apr 2018 13:36:20 +0100
Subject: Remove unnecessary masking of the result of known short instructions

---
 test/libevmasm/Optimiser.cpp | 69 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

(limited to 'test/libevmasm/Optimiser.cpp')

diff --git a/test/libevmasm/Optimiser.cpp b/test/libevmasm/Optimiser.cpp
index 089be45d..4b399a14 100644
--- a/test/libevmasm/Optimiser.cpp
+++ b/test/libevmasm/Optimiser.cpp
@@ -1072,6 +1072,75 @@ BOOST_AUTO_TEST_CASE(cse_sub_zero)
 	});
 }
 
+BOOST_AUTO_TEST_CASE(cse_remove_unwanted_masking_of_address)
+{
+	vector<Instruction> ops{
+		Instruction::ADDRESS,
+		Instruction::CALLER,
+		Instruction::ORIGIN,
+		Instruction::COINBASE
+	};
+	for (auto const& op: ops)
+	{
+		checkCSE({
+			u256("0xffffffffffffffffffffffffffffffffffffffff"),
+			op,
+			Instruction::AND
+		}, {
+			op
+		});
+
+		checkCSE({
+			op,
+			u256("0xffffffffffffffffffffffffffffffffffffffff"),
+			Instruction::AND
+		}, {
+			op
+		});
+
+		// do not remove mask for other masking
+		checkCSE({
+			u256(1234),
+			op,
+			Instruction::AND
+		}, {
+			op,
+			u256(1234),
+			Instruction::AND
+		});
+
+		checkCSE({
+			op,
+			u256(1234),
+			Instruction::AND
+		}, {
+			u256(1234),
+			op,
+			Instruction::AND
+		});
+	}
+
+	// leave other opcodes untouched
+	checkCSE({
+		u256("0xffffffffffffffffffffffffffffffffffffffff"),
+		Instruction::CALLVALUE,
+		Instruction::AND
+	}, {
+		Instruction::CALLVALUE,
+		u256("0xffffffffffffffffffffffffffffffffffffffff"),
+		Instruction::AND
+	});
+
+	checkCSE({
+		Instruction::CALLVALUE,
+		u256("0xffffffffffffffffffffffffffffffffffffffff"),
+		Instruction::AND
+	}, {
+		u256("0xffffffffffffffffffffffffffffffffffffffff"),
+		Instruction::CALLVALUE,
+		Instruction::AND
+	});
+}
 
 BOOST_AUTO_TEST_SUITE_END()
 
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