Merge pull request #3797 from ethereum/shift-constantinople

Use native shift instructions on Constantinople

1 files changed, 15 insertions, 8 deletions

diff --git a/libsolidity/codegen/CompilerUtils.cpp b/libsolidity/codegen/CompilerUtils.cpp
index 4af7d905..48b77eb3 100644
--- a/libsolidity/codegen/CompilerUtils.cpp
+++ b/libsolidity/codegen/CompilerUtils.cpp
@@ -599,15 +599,15 @@ void CompilerUtils::splitExternalFunctionType(bool _leftAligned)
 	if (_leftAligned)
 	{
 		m_context << Instruction::DUP1;
-		rightShiftNumberOnStack(64 + 32, false);
+		rightShiftNumberOnStack(64 + 32);
 		// <input> <address>
 		m_context << Instruction::SWAP1;
-		rightShiftNumberOnStack(64, false);
+		rightShiftNumberOnStack(64);
 	}
 	else
 	{
 		m_context << Instruction::DUP1;
-		rightShiftNumberOnStack(32, false);
+		rightShiftNumberOnStack(32);
 		m_context << ((u256(1) << 160) - 1) << Instruction::AND << Instruction::SWAP1;
 	}
 	m_context << u256(0xffffffffUL) << Instruction::AND;
@@ -675,7 +675,7 @@ void CompilerUtils::convertType(
 			// conversion from bytes to integer. no need to clean the high bit
 			// only to shift right because of opposite alignment
 			IntegerType const& targetIntegerType = dynamic_cast<IntegerType const&>(_targetType);
-			rightShiftNumberOnStack(256 - typeOnStack.numBytes() * 8, false);
+			rightShiftNumberOnStack(256 - typeOnStack.numBytes() * 8);
 			if (targetIntegerType.numBits() < typeOnStack.numBytes() * 8)
 				convertType(IntegerType(typeOnStack.numBytes() * 8), _targetType, _cleanupNeeded);
 		}
@@ -1242,7 +1242,7 @@ unsigned CompilerUtils::loadFromMemoryHelper(Type const& _type, bool _fromCallda
 		bool leftAligned = _type.category() == Type::Category::FixedBytes;
 		// add leading or trailing zeros by dividing/multiplying depending on alignment
 		int shiftFactor = (32 - numBytes) * 8;
-		rightShiftNumberOnStack(shiftFactor, false);
+		rightShiftNumberOnStack(shiftFactor);
 		if (leftAligned)
 			leftShiftNumberOnStack(shiftFactor);
 	}
@@ -1265,13 +1265,20 @@ void CompilerUtils::cleanHigherOrderBits(IntegerType const& _typeOnStack)
 void CompilerUtils::leftShiftNumberOnStack(unsigned _bits)
 {
 	solAssert(_bits < 256, "");
-	m_context << (u256(1) << _bits) << Instruction::MUL;
+	if (m_context.evmVersion().hasBitwiseShifting())
+		m_context << _bits << Instruction::SHL;
+	else
+		m_context << (u256(1) << _bits) << Instruction::MUL;
 }
 
-void CompilerUtils::rightShiftNumberOnStack(unsigned _bits, bool _isSigned)
+void CompilerUtils::rightShiftNumberOnStack(unsigned _bits)
 {
 	solAssert(_bits < 256, "");
-	m_context << (u256(1) << _bits) << Instruction::SWAP1 << (_isSigned ? Instruction::SDIV : Instruction::DIV);
+	// NOTE: If we add signed right shift, SAR rounds differently than SDIV
+	if (m_context.evmVersion().hasBitwiseShifting())
+		m_context << _bits << Instruction::SHR;
+	else
+		m_context << (u256(1) << _bits) << Instruction::SWAP1 << Instruction::DIV;
 }
 
 unsigned CompilerUtils::prepareMemoryStore(Type const& _type, bool _padToWords)