Use inline assembly suggested by @chriseth

#1091 (comment)
ethereum · Sep 13, 2016 · 1a6eef6 · 1a6eef6
1 parent a518a35
commit 1a6eef6
Showing 1 changed file with 7 additions and 8 deletions.
diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp
@@ -1340,14 +1340,13 @@ void ExpressionCompiler::appendArithmeticOperatorCode(Token::Value _operator, Ty
 		// Test for (minInt) / (-1)
 		if (c_isSigned && _operator == Token::Div)
 		{
-			m_context << Instruction::DUP1 // 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.appendInlineAssembly(R"(
+				and(
+					eq(x, exp(2, 255)), // x == 2**256 (min int)
+					iszero(not(y)) // y == -1
+				)
+			)",
+			{"y", "x"});
 			m_context.appendConditionalJumpTo(m_context.errorTag());
 		}