Merge pull request #4084 from ethereum/signedRightShift

[BREAKING] Use proper SAR for signed right shifts and emulate on pre-constantinople.

5 files changed, 160 insertions, 70 deletions

diff --git a/Changelog.md b/Changelog.md
index 0050f9a6..d5b440b2 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -8,6 +8,7 @@ Breaking Changes:
  * Commandline interface: Require ``-`` if standard input is used as source.
  * General: New keywords: ``calldata``
  * General: ``continue`` in a ``do...while`` loop jumps to the condition (it used to jump to the loop body). Warning: this may silently change the semantics of existing code.
+ * General: Signed right shift uses proper arithmetic shift, i.e. rounding towards negative infinity. Warning: this may silently change the semantics of existing code!
  * Introduce ``emit`` as a keyword instead of parsing it as identifier.
  * Type Checker: Disallow arithmetic operations for Boolean variables.
  * Disallow trailing dots that are not followed by a number.
diff --git a/docs/types.rst b/docs/types.rst
index 08b74241..009896d5 100644
--- a/docs/types.rst
+++ b/docs/types.rst
@@ -60,15 +60,14 @@ operators are :ref:`literals<rational_literals>` (or literal expressions).
 Division by zero and modulus with zero throws a runtime exception.
 
 The result of a shift operation is the type of the left operand. The
-expression ``x << y`` is equivalent to ``x * 2**y``, and ``x >> y`` is
-equivalent to ``x / 2**y``. This means that shifting negative numbers
-sign extends. Shifting by a negative amount throws a runtime exception.
+expression ``x << y`` is equivalent to ``x * 2**y``, and, for positive integers,
+``x >> y`` is equivalent to ``x / 2**y``. For negative ``x``, ``x >> y``
+is equivalent to dividing by a power of ``2`` while rounding down (towards negative infinity).
+Shifting by a negative amount throws a runtime exception.
 
 .. warning::
-    The results produced by shift right of negative values of signed integer types is different from those produced
-    by other programming languages. In Solidity, shift right maps to division so the shifted negative values
-    are going to be rounded towards zero (truncated). In other programming languages the shift right of negative values
-    works like division with rounding down (towards negative infinity).
+    Before version ``0.5.0`` a right shift ``x >> y`` for negative ``x`` was equivalent to ``x / 2**y``,
+    i.e. right shifts used rounding towards zero instead of rounding towards negative infinity.
 
 .. index:: ! ufixed, ! fixed, ! fixed point number
 
diff --git a/libsolidity/ast/Types.cpp b/libsolidity/ast/Types.cpp
index 1e0565c0..94e04b6a 100644
--- a/libsolidity/ast/Types.cpp
+++ b/libsolidity/ast/Types.cpp
@@ -1084,9 +1084,16 @@ TypePointer RationalNumberType::binaryOperatorResult(Token::Value _operator, Typ
 			{
 				uint32_t exponent = other.m_value.numerator().convert_to<uint32_t>();
 				if (exponent > mostSignificantBit(boost::multiprecision::abs(m_value.numerator())))
-					value = 0;
+					value = m_value.numerator() < 0 ? -1 : 0;
 				else
-					value = rational(m_value.numerator() / boost::multiprecision::pow(bigint(2), exponent), 1);
+				{
+					if (m_value.numerator() < 0)
+						// add 1 to the negative value before dividing to get a result that is strictly too large
+						// subtract 1 afterwards to round towards negative infinity
+						value = rational((m_value.numerator() + 1) / boost::multiprecision::pow(bigint(2), exponent) - bigint(1), 1);
+					else
+						value = rational(m_value.numerator() / boost::multiprecision::pow(bigint(2), exponent), 1);
+				}
 			}
 			break;
 		}
diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp
index 93d440c8..0470c3ec 100644
--- a/libsolidity/codegen/ExpressionCompiler.cpp
+++ b/libsolidity/codegen/ExpressionCompiler.cpp
@@ -1737,11 +1737,36 @@ void ExpressionCompiler::appendShiftOperatorCode(Token::Value _operator, Type co
 			m_context << u256(2) << Instruction::EXP << Instruction::MUL;
 		break;
 	case Token::SAR:
-		// NOTE: SAR rounds differently than SDIV
-		if (m_context.evmVersion().hasBitwiseShifting() && !c_valueSigned)
-			m_context << Instruction::SHR;
+		if (m_context.evmVersion().hasBitwiseShifting())
+			m_context << (c_valueSigned ? Instruction::SAR : Instruction::SHR);
 		else
-			m_context << u256(2) << Instruction::EXP << Instruction::SWAP1 << (c_valueSigned ? Instruction::SDIV : Instruction::DIV);
+		{
+			if (c_valueSigned)
+				// In the following assembly snippet, xor_mask will be zero, if value_to_shift is positive.
+				// Therefor xor'ing with xor_mask is the identity and the computation reduces to
+				// div(value_to_shift, exp(2, shift_amount)), which is correct, since for positive values
+				// arithmetic right shift is dividing by a power of two (which, as a bitwise operation, results
+				// in discarding bits on the right and filling with zeros from the left).
+				// For negative values arithmetic right shift, viewed as a bitwise operation, discards bits to the
+				// right and fills in ones from the left. This is achieved as follows:
+				// If value_to_shift is negative, then xor_mask will have all bits set, so xor'ing with xor_mask
+				// will flip all bits. First all bits in value_to_shift are flipped. As for the positive case,
+				// dividing by a power of two using integer arithmetic results in discarding bits to the right
+				// and filling with zeros from the left. Flipping all bits in the result again, turns all zeros
+				// on the left to ones and restores the non-discarded, shifted bits to their original value (they
+				// have now been flipped twice). In summary we now have discarded bits to the right and filled with
+				// ones from the left, i.e. we have performed an arithmetic right shift.
+				m_context.appendInlineAssembly(R"({
+					let xor_mask := sub(0, slt(value_to_shift, 0))
+					value_to_shift := xor(div(xor(value_to_shift, xor_mask), exp(2, shift_amount)), xor_mask)
+				})", {"value_to_shift", "shift_amount"});
+			else
+				m_context.appendInlineAssembly(R"({
+					value_to_shift := div(value_to_shift, exp(2, shift_amount))
+				})", {"value_to_shift", "shift_amount"});
+			m_context << Instruction::POP;
+
+		}
 		break;
 	case Token::SHR:
 	default:
diff --git a/test/libsolidity/SolidityEndToEndTest.cpp b/test/libsolidity/SolidityEndToEndTest.cpp
index b53a9294..3b3cc4f7 100644
--- a/test/libsolidity/SolidityEndToEndTest.cpp
+++ b/test/libsolidity/SolidityEndToEndTest.cpp
@@ -10487,6 +10487,7 @@ BOOST_AUTO_TEST_CASE(shift_right)
 	ABI_CHECK(callContractFunction("f(uint256,uint256)", u256(0x4266), u256(8)), encodeArgs(u256(0x42)));
 	ABI_CHECK(callContractFunction("f(uint256,uint256)", u256(0x4266), u256(16)), encodeArgs(u256(0)));
 	ABI_CHECK(callContractFunction("f(uint256,uint256)", u256(0x4266), u256(17)), encodeArgs(u256(0)));
+	ABI_CHECK(callContractFunction("f(uint256,uint256)", u256(1)<<255, u256(5)), encodeArgs(u256(1)<<250));
 }
 
 BOOST_AUTO_TEST_CASE(shift_right_garbled)
@@ -10583,16 +10584,73 @@ BOOST_AUTO_TEST_CASE(shift_right_negative_lvalue)
 	compileAndRun(sourceCode, 0, "C");
 	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(0)), encodeArgs(u256(-4266)));
 	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(1)), encodeArgs(u256(-2133)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(4)), encodeArgs(u256(-266)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(8)), encodeArgs(u256(-16)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(16)), encodeArgs(u256(0)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(17)), encodeArgs(u256(0)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(4)), encodeArgs(u256(-267)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(8)), encodeArgs(u256(-17)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(16)), encodeArgs(u256(-1)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(17)), encodeArgs(u256(-1)));
 	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(0)), encodeArgs(u256(-4267)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(1)), encodeArgs(u256(-2133)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(4)), encodeArgs(u256(-266)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(8)), encodeArgs(u256(-16)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(16)), encodeArgs(u256(0)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(17)), encodeArgs(u256(0)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(1)), encodeArgs(u256(-2134)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(4)), encodeArgs(u256(-267)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(8)), encodeArgs(u256(-17)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(16)), encodeArgs(u256(-1)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(17)), encodeArgs(u256(-1)));
+}
+
+BOOST_AUTO_TEST_CASE(shift_right_negative_literal)
+{
+	char const* sourceCode = R"(
+			contract C {
+				function f1() pure returns (bool) {
+					return (-4266 >> 0) == -4266;
+				}
+				function f2() pure returns (bool) {
+					return (-4266 >> 1) == -2133;
+				}
+				function f3() pure returns (bool) {
+					return (-4266 >> 4) == -267;
+				}
+				function f4() pure returns (bool) {
+					return (-4266 >> 8) == -17;
+				}
+				function f5() pure returns (bool) {
+					return (-4266 >> 16) == -1;
+				}
+				function f6() pure returns (bool) {
+					return (-4266 >> 17) == -1;
+				}
+				function g1() pure returns (bool) {
+					return (-4267 >> 0) == -4267;
+				}
+				function g2() pure returns (bool) {
+					return (-4267 >> 1) == -2134;
+				}
+				function g3() pure returns (bool) {
+					return (-4267 >> 4) == -267;
+				}
+				function g4() pure returns (bool) {
+					return (-4267 >> 8) == -17;
+				}
+				function g5() pure returns (bool) {
+					return (-4267 >> 16) == -1;
+				}
+				function g6() pure returns (bool) {
+					return (-4267 >> 17) == -1;
+				}
+			}
+		)";
+	compileAndRun(sourceCode, 0, "C");
+	ABI_CHECK(callContractFunction("f1()"), encodeArgs(true));
+	ABI_CHECK(callContractFunction("f2()"), encodeArgs(true));
+	ABI_CHECK(callContractFunction("f3()"), encodeArgs(true));
+	ABI_CHECK(callContractFunction("f4()"), encodeArgs(true));
+	ABI_CHECK(callContractFunction("f5()"), encodeArgs(true));
+	ABI_CHECK(callContractFunction("f6()"), encodeArgs(true));
+	ABI_CHECK(callContractFunction("g1()"), encodeArgs(true));
+	ABI_CHECK(callContractFunction("g2()"), encodeArgs(true));
+	ABI_CHECK(callContractFunction("g3()"), encodeArgs(true));
+	ABI_CHECK(callContractFunction("g4()"), encodeArgs(true));
+	ABI_CHECK(callContractFunction("g5()"), encodeArgs(true));
+	ABI_CHECK(callContractFunction("g6()"), encodeArgs(true));
 }
 
 BOOST_AUTO_TEST_CASE(shift_right_negative_lvalue_int8)
@@ -10607,16 +10665,16 @@ BOOST_AUTO_TEST_CASE(shift_right_negative_lvalue_int8)
 	compileAndRun(sourceCode, 0, "C");
 	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-66), u256(0)), encodeArgs(u256(-66)));
 	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-66), u256(1)), encodeArgs(u256(-33)));
-	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-66), u256(4)), encodeArgs(u256(-4)));
-	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-66), u256(8)), encodeArgs(u256(0)));
-	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-66), u256(16)), encodeArgs(u256(0)));
-	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-66), u256(17)), encodeArgs(u256(0)));
+	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-66), u256(4)), encodeArgs(u256(-5)));
+	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-66), u256(8)), encodeArgs(u256(-1)));
+	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-66), u256(16)), encodeArgs(u256(-1)));
+	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-66), u256(17)), encodeArgs(u256(-1)));
 	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-67), u256(0)), encodeArgs(u256(-67)));
-	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-67), u256(1)), encodeArgs(u256(-33)));
-	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-67), u256(4)), encodeArgs(u256(-4)));
-	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-67), u256(8)), encodeArgs(u256(0)));
-	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-67), u256(16)), encodeArgs(u256(0)));
-	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-67), u256(17)), encodeArgs(u256(0)));
+	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-67), u256(1)), encodeArgs(u256(-34)));
+	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-67), u256(4)), encodeArgs(u256(-5)));
+	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-67), u256(8)), encodeArgs(u256(-1)));
+	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-67), u256(16)), encodeArgs(u256(-1)));
+	ABI_CHECK(callContractFunction("f(int8,int8)", u256(-67), u256(17)), encodeArgs(u256(-1)));
 }
 
 BOOST_AUTO_TEST_CASE(shift_right_negative_lvalue_signextend_int8)
@@ -10630,10 +10688,10 @@ BOOST_AUTO_TEST_CASE(shift_right_negative_lvalue_signextend_int8)
 		)";
 	compileAndRun(sourceCode, 0, "C");
 	ABI_CHECK(callContractFunction("f(int8,int8)", u256(0x99u), u256(0)), encodeArgs(u256(-103)));
-	ABI_CHECK(callContractFunction("f(int8,int8)", u256(0x99u), u256(1)), encodeArgs(u256(-51)));
-	ABI_CHECK(callContractFunction("f(int8,int8)", u256(0x99u), u256(2)), encodeArgs(u256(-25)));
-	ABI_CHECK(callContractFunction("f(int8,int8)", u256(0x99u), u256(4)), encodeArgs(u256(-6)));
-	ABI_CHECK(callContractFunction("f(int8,int8)", u256(0x99u), u256(8)), encodeArgs(u256(0)));
+	ABI_CHECK(callContractFunction("f(int8,int8)", u256(0x99u), u256(1)), encodeArgs(u256(-52)));
+	ABI_CHECK(callContractFunction("f(int8,int8)", u256(0x99u), u256(2)), encodeArgs(u256(-26)));
+	ABI_CHECK(callContractFunction("f(int8,int8)", u256(0x99u), u256(4)), encodeArgs(u256(-7)));
+	ABI_CHECK(callContractFunction("f(int8,int8)", u256(0x99u), u256(8)), encodeArgs(u256(-1)));
 }
 
 BOOST_AUTO_TEST_CASE(shift_right_negative_lvalue_signextend_int16)
@@ -10647,10 +10705,10 @@ BOOST_AUTO_TEST_CASE(shift_right_negative_lvalue_signextend_int16)
 		)";
 	compileAndRun(sourceCode, 0, "C");
 	ABI_CHECK(callContractFunction("f(int16,int16)", u256(0xFF99u), u256(0)), encodeArgs(u256(-103)));
-	ABI_CHECK(callContractFunction("f(int16,int16)", u256(0xFF99u), u256(1)), encodeArgs(u256(-51)));
-	ABI_CHECK(callContractFunction("f(int16,int16)", u256(0xFF99u), u256(2)), encodeArgs(u256(-25)));
-	ABI_CHECK(callContractFunction("f(int16,int16)", u256(0xFF99u), u256(4)), encodeArgs(u256(-6)));
-	ABI_CHECK(callContractFunction("f(int16,int16)", u256(0xFF99u), u256(8)), encodeArgs(u256(0)));
+	ABI_CHECK(callContractFunction("f(int16,int16)", u256(0xFF99u), u256(1)), encodeArgs(u256(-52)));
+	ABI_CHECK(callContractFunction("f(int16,int16)", u256(0xFF99u), u256(2)), encodeArgs(u256(-26)));
+	ABI_CHECK(callContractFunction("f(int16,int16)", u256(0xFF99u), u256(4)), encodeArgs(u256(-7)));
+	ABI_CHECK(callContractFunction("f(int16,int16)", u256(0xFF99u), u256(8)), encodeArgs(u256(-1)));
 }
 
 BOOST_AUTO_TEST_CASE(shift_right_negative_lvalue_signextend_int32)
@@ -10664,10 +10722,10 @@ BOOST_AUTO_TEST_CASE(shift_right_negative_lvalue_signextend_int32)
 		)";
 	compileAndRun(sourceCode, 0, "C");
 	ABI_CHECK(callContractFunction("f(int32,int32)", u256(0xFFFFFF99u), u256(0)), encodeArgs(u256(-103)));
-	ABI_CHECK(callContractFunction("f(int32,int32)", u256(0xFFFFFF99u), u256(1)), encodeArgs(u256(-51)));
-	ABI_CHECK(callContractFunction("f(int32,int32)", u256(0xFFFFFF99u), u256(2)), encodeArgs(u256(-25)));
-	ABI_CHECK(callContractFunction("f(int32,int32)", u256(0xFFFFFF99u), u256(4)), encodeArgs(u256(-6)));
-	ABI_CHECK(callContractFunction("f(int32,int32)", u256(0xFFFFFF99u), u256(8)), encodeArgs(u256(0)));
+	ABI_CHECK(callContractFunction("f(int32,int32)", u256(0xFFFFFF99u), u256(1)), encodeArgs(u256(-52)));
+	ABI_CHECK(callContractFunction("f(int32,int32)", u256(0xFFFFFF99u), u256(2)), encodeArgs(u256(-26)));
+	ABI_CHECK(callContractFunction("f(int32,int32)", u256(0xFFFFFF99u), u256(4)), encodeArgs(u256(-7)));
+	ABI_CHECK(callContractFunction("f(int32,int32)", u256(0xFFFFFF99u), u256(8)), encodeArgs(u256(-1)));
 }
 
 
@@ -10683,16 +10741,16 @@ BOOST_AUTO_TEST_CASE(shift_right_negative_lvalue_int16)
 	compileAndRun(sourceCode, 0, "C");
 	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4266), u256(0)), encodeArgs(u256(-4266)));
 	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4266), u256(1)), encodeArgs(u256(-2133)));
-	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4266), u256(4)), encodeArgs(u256(-266)));
-	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4266), u256(8)), encodeArgs(u256(-16)));
-	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4266), u256(16)), encodeArgs(u256(0)));
-	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4266), u256(17)), encodeArgs(u256(0)));
+	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4266), u256(4)), encodeArgs(u256(-267)));
+	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4266), u256(8)), encodeArgs(u256(-17)));
+	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4266), u256(16)), encodeArgs(u256(-1)));
+	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4266), u256(17)), encodeArgs(u256(-1)));
 	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4267), u256(0)), encodeArgs(u256(-4267)));
-	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4267), u256(1)), encodeArgs(u256(-2133)));
-	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4267), u256(4)), encodeArgs(u256(-266)));
-	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4267), u256(8)), encodeArgs(u256(-16)));
-	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4267), u256(16)), encodeArgs(u256(0)));
-	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4267), u256(17)), encodeArgs(u256(0)));
+	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4267), u256(1)), encodeArgs(u256(-2134)));
+	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4267), u256(4)), encodeArgs(u256(-267)));
+	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4267), u256(8)), encodeArgs(u256(-17)));
+	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4267), u256(16)), encodeArgs(u256(-1)));
+	ABI_CHECK(callContractFunction("f(int16,int16)", u256(-4267), u256(17)), encodeArgs(u256(-1)));
 }
 
 BOOST_AUTO_TEST_CASE(shift_right_negative_lvalue_int32)
@@ -10707,16 +10765,16 @@ BOOST_AUTO_TEST_CASE(shift_right_negative_lvalue_int32)
 	compileAndRun(sourceCode, 0, "C");
 	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4266), u256(0)), encodeArgs(u256(-4266)));
 	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4266), u256(1)), encodeArgs(u256(-2133)));
-	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4266), u256(4)), encodeArgs(u256(-266)));
-	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4266), u256(8)), encodeArgs(u256(-16)));
-	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4266), u256(16)), encodeArgs(u256(0)));
-	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4266), u256(17)), encodeArgs(u256(0)));
+	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4266), u256(4)), encodeArgs(u256(-267)));
+	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4266), u256(8)), encodeArgs(u256(-17)));
+	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4266), u256(16)), encodeArgs(u256(-1)));
+	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4266), u256(17)), encodeArgs(u256(-1)));
 	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4267), u256(0)), encodeArgs(u256(-4267)));
-	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4267), u256(1)), encodeArgs(u256(-2133)));
-	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4267), u256(4)), encodeArgs(u256(-266)));
-	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4267), u256(8)), encodeArgs(u256(-16)));
-	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4267), u256(16)), encodeArgs(u256(0)));
-	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4267), u256(17)), encodeArgs(u256(0)));
+	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4267), u256(1)), encodeArgs(u256(-2134)));
+	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4267), u256(4)), encodeArgs(u256(-267)));
+	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4267), u256(8)), encodeArgs(u256(-17)));
+	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4267), u256(16)), encodeArgs(u256(-1)));
+	ABI_CHECK(callContractFunction("f(int32,int32)", u256(-4267), u256(17)), encodeArgs(u256(-1)));
 }
 
 BOOST_AUTO_TEST_CASE(shift_right_negative_lvalue_assignment)
@@ -10732,16 +10790,16 @@ BOOST_AUTO_TEST_CASE(shift_right_negative_lvalue_assignment)
 	compileAndRun(sourceCode, 0, "C");
 	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(0)), encodeArgs(u256(-4266)));
 	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(1)), encodeArgs(u256(-2133)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(4)), encodeArgs(u256(-266)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(8)), encodeArgs(u256(-16)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(16)), encodeArgs(u256(0)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(17)), encodeArgs(u256(0)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(4)), encodeArgs(u256(-267)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(8)), encodeArgs(u256(-17)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(16)), encodeArgs(u256(-1)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4266), u256(17)), encodeArgs(u256(-1)));
 	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(0)), encodeArgs(u256(-4267)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(1)), encodeArgs(u256(-2133)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(4)), encodeArgs(u256(-266)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(8)), encodeArgs(u256(-16)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(16)), encodeArgs(u256(0)));
-	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(17)), encodeArgs(u256(0)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(1)), encodeArgs(u256(-2134)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(4)), encodeArgs(u256(-267)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(8)), encodeArgs(u256(-17)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(16)), encodeArgs(u256(-1)));
+	ABI_CHECK(callContractFunction("f(int256,int256)", u256(-4267), u256(17)), encodeArgs(u256(-1)));
 }
 
 BOOST_AUTO_TEST_CASE(shift_negative_rvalue)