From 22bfd3da41ae9efa6e68e884f722502ab3adcf50 Mon Sep 17 00:00:00 2001 From: Alex Beregszaszi Date: Thu, 29 Mar 2018 09:56:51 +0100 Subject: Use native shift instructions on Constantinople --- libsolidity/codegen/ExpressionCompiler.cpp | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'libsolidity/codegen/ExpressionCompiler.cpp') diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp index 3cf46a9d..1a33fe7c 100644 --- a/libsolidity/codegen/ExpressionCompiler.cpp +++ b/libsolidity/codegen/ExpressionCompiler.cpp @@ -1706,13 +1706,22 @@ void ExpressionCompiler::appendShiftOperatorCode(Token::Value _operator, Type co m_context.appendConditionalInvalid(); } + m_context << Instruction::SWAP1; + // stack: value_to_shift shift_amount + switch (_operator) { case Token::SHL: - m_context << Instruction::SWAP1 << u256(2) << Instruction::EXP << Instruction::MUL; + if (m_context.evmVersion().hasBitwiseShifting()) + m_context << Instruction::SHL; + else + m_context << u256(2) << Instruction::EXP << Instruction::MUL; break; case Token::SAR: - m_context << Instruction::SWAP1 << u256(2) << Instruction::EXP << Instruction::SWAP1 << (c_valueSigned ? Instruction::SDIV : Instruction::DIV); + 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); break; case Token::SHR: default: -- cgit v1.2.3 From 52c94418795f829c4a225fdf4742eec7a1961232 Mon Sep 17 00:00:00 2001 From: Alex Beregszaszi Date: Fri, 6 Apr 2018 14:54:21 +0200 Subject: Do not use SAR instead of SDIV in shifts because it rounds differently --- libsolidity/codegen/ExpressionCompiler.cpp | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'libsolidity/codegen/ExpressionCompiler.cpp') diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp index 1a33fe7c..019867c5 100644 --- a/libsolidity/codegen/ExpressionCompiler.cpp +++ b/libsolidity/codegen/ExpressionCompiler.cpp @@ -1718,8 +1718,9 @@ void ExpressionCompiler::appendShiftOperatorCode(Token::Value _operator, Type co m_context << u256(2) << Instruction::EXP << Instruction::MUL; break; case Token::SAR: - if (m_context.evmVersion().hasBitwiseShifting()) - m_context << (c_valueSigned ? Instruction::SAR : Instruction::SHR); + // NOTE: SAR rounds differently than SDIV + if (m_context.evmVersion().hasBitwiseShifting() && !c_valueSigned) + m_context << Instruction::SHR; else m_context << u256(2) << Instruction::EXP << Instruction::SWAP1 << (c_valueSigned ? Instruction::SDIV : Instruction::DIV); break; -- cgit v1.2.3 From 2968639406888d97bfae70e4adf41674ac60fd83 Mon Sep 17 00:00:00 2001 From: chriseth Date: Fri, 6 Apr 2018 16:25:13 +0200 Subject: Removed signed shift right from the utilities. --- libsolidity/codegen/ExpressionCompiler.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'libsolidity/codegen/ExpressionCompiler.cpp') diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp index 019867c5..a8222e21 100644 --- a/libsolidity/codegen/ExpressionCompiler.cpp +++ b/libsolidity/codegen/ExpressionCompiler.cpp @@ -548,7 +548,7 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall) if (m_context.runtimeContext()) // We have a runtime context, so we need the creation part. - utils().rightShiftNumberOnStack(32, false); + utils().rightShiftNumberOnStack(32); else // Extract the runtime part. m_context << ((u256(1) << 32) - 1) << Instruction::AND; -- cgit v1.2.3