Optimizer for memory.

SolidityOptimizer.cpp

@@ -444,6 +444,59 @@ BOOST_AUTO_TEST_CASE(cse_interleaved_storage_at_known_location_offset)
 	});
 }
 
+BOOST_AUTO_TEST_CASE(cse_interleaved_memory_at_known_location_offset)
+{
+	// stores and reads to/from two locations which are known to be different,
+	// should not optimize away the first store, because the location overlaps with the load,
+	// but it should optimize away the second, because we know that the location is different by 32
+	AssemblyItems input{
+		u256(0x50),
+		Instruction::DUP2,
+		u256(2),
+		Instruction::ADD,
+		Instruction::MSTORE, // ["DUP1"+2] = 0x50
+		u256(0x60),
+		Instruction::DUP2,
+		u256(32),
+		Instruction::ADD,
+		Instruction::MSTORE, // ["DUP1"+32] = 0x60
+		Instruction::DUP1,
+		Instruction::MLOAD, // read from "DUP1"
+		u256(0x70),
+		Instruction::DUP3,
+		u256(32),
+		Instruction::ADD,
+		Instruction::MSTORE, // ["DUP1"+32] = 0x70
+		u256(0x80),
+		Instruction::DUP3,
+		u256(2),
+		Instruction::ADD,
+		Instruction::MSTORE, // ["DUP1"+2] = 0x80
+	};
+	// If the actual code changes too much, we could also simply check that the output contains
+	// exactly 3 MSTORE and exactly 1 MLOAD instruction.
+	checkCSE(input, {
+		u256(0x50),
+		u256(2),
+		Instruction::DUP3,
+		Instruction::ADD,
+		Instruction::SWAP1,
+		Instruction::DUP2,
+		Instruction::MSTORE, // ["DUP1"+2] = 0x50
+		Instruction::DUP2,
+		Instruction::MLOAD, // read from "DUP1"
+		u256(0x70),
+		u256(32),
+		Instruction::DUP5,
+		Instruction::ADD,
+		Instruction::MSTORE, // ["DUP1"+32] = 0x70
+		u256(0x80),
+		Instruction::SWAP1,
+		Instruction::SWAP2,
+		Instruction::MSTORE // ["DUP1"+2] = 0x80
+	});
+}
+
 BOOST_AUTO_TEST_CASE(cse_deep_stack)
 {
 	AssemblyItems input{