Zend LLVM Extension
Google Summer of Code - Zend LLVM Extension、これは面白そうな試み。ZendオペコードをLLVMのIR(中間コード)に変換して実行するZend extensionを作るようです。
Hence from the users perspective, the extension would behave much like existing opcode caches, like eAccelerator, but the crucial difference is that LLVM is allowed to perform its aggressive optimizations, which should improve the performance further if enough Zend opcodes are converted to native LLVM IR.