Add a test for (minInt) / (-1)

The result is not within the expressible range of signed 256 bit integer.
ethereum · Sep 13, 2016 · 5b01e0a · 5b01e0a
1 parent 596f8ac
commit 5b01e0a
Showing 1 changed file with 14 additions and 0 deletions.
diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp
@@ -1337,6 +1337,20 @@ void ExpressionCompiler::appendArithmeticOperatorCode(Token::Value _operator, Ty
 		m_context << Instruction::DUP2 << Instruction::ISZERO;
 		m_context.appendConditionalJumpTo(m_context.errorTag());
 
+		// Test for (minInt) / (-1)
+		if (c_isSigned && _operator == Token::Div)
+		{
+			m_context << Instruction::DUP1 << Instruction::NOT  // ~x
+				<< u256(2) << u256(255) << Instruction::EXP // 2 ** 255
+				<< Instruction::EQ;
+			// stack: (x == minInt), x, y
+			m_context << Instruction::DUP3 << Instruction::NOT // ~y
+				<< Instruction::ISZERO;
+			// stack: (y == (-1)), (x == minInt), x, y
+			m_context << Instruction::AND;
+			m_context.appendConditionalJumpTo(m_context.errorTag());
+		}
+
 		if (_operator == Token::Div)
 			m_context << (c_isSigned ? Instruction::SDIV : Instruction::DIV);
 		else