Trusted Execution Environment(TEE) Based Application Development/
Enclave EVM (eEVM) is an open-source, standalone, embeddable, C++ implementation of the Ethereum Virtual Machine. It was originally built to run within a TEE (ie, SGX enclave) on top of the Open Enclave,for use with Microsoft's Confidential Consortium Blockchain Framework. Coco 
What is Open Enclave SDK?
The implementation ignores all gas costs - gas is not spent, tracked, or updated during execution, and execution will never throw an outofgas exception. However, it may still be necessary to pass a sensible initial gas value to evm::Processor::run() in case the bytecode calculates or verifies gas budgets itself.
So far, the code is not particularly optimized in any dimension. In fact, it is in experimental state. Github repos: eEVM and openenclave