Save double encode call for sha3.

1 files changed, 16 insertions, 8 deletions

diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp
index e579264e..ecbd0243 100644
--- a/libsolidity/codegen/ExpressionCompiler.cpp
+++ b/libsolidity/codegen/ExpressionCompiler.cpp
@@ -699,16 +699,24 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
 		}
 		case FunctionType::Kind::SHA3:
 		{
-			TypePointers argumentTypes;
-			for (auto const& arg: arguments)
+			solAssert(arguments.size() == 1, "");
+			solAssert(!function.padArguments(), "");
+			TypePointer const& argType = arguments.front()->annotation().type;
+			solAssert(argType, "");
+			arguments.front()->accept(*this);
+			// Optimization: If type is bytes or string, then do not encode,
+			// but directly compute keccak256 on memory.
+			if (*argType == ArrayType(DataLocation::Memory) || *argType == ArrayType(DataLocation::Memory, true))
 			{
-				arg->accept(*this);
-				argumentTypes.push_back(arg->annotation().type);
+				ArrayUtils(m_context).retrieveLength(ArrayType(DataLocation::Memory));
+				m_context << Instruction::SWAP1 << u256(0x20) << Instruction::ADD;
+			}
+			else
+			{
+				utils().fetchFreeMemoryPointer();
+				utils().packedEncode({argType}, TypePointers());
+				utils().toSizeAfterFreeMemoryPointer();
 			}
-			utils().fetchFreeMemoryPointer();
-			solAssert(!function.padArguments(), "");
-			utils().packedEncode(argumentTypes, TypePointers());
-			utils().toSizeAfterFreeMemoryPointer();
 			m_context << Instruction::KECCAK256;
 			break;
 		}