Does anyone know of attempts to add CPU instructions that allow JITs and compilers to mitigate Spectre by using speculation-safe instructions for safety critica

Does anyone know of attempts to add CPU instructions that allow JITs and compilers to mitigate Spectre by using speculation-safe instructions for safety critical checks? I could imagine a "load if less than" or similar instruction, which the compiler could use to incorporate the safety check into the load instruction and avoid a separate branch that could be mispredicted. Such an instruction would be documented to have no side effects (even timing side effects) if the condition were not met.