protected boolean isRegisterKnown(PcodeThread<?> thread, Register register) {
		Trace trace = platform.getTrace();
		TraceThread traceThread =
			trace.getThreadManager().getLiveThreadByPath(snap, thread.getName());
		TraceMemorySpace space =
			trace.getMemoryManager().getMemoryRegisterSpace(traceThread, false);
		if (space == null) {
			return false;
		}
		return space.getState(platform, snap, register) == TraceMemoryState.KNOWN;
	}
Check if a register has a {@link TraceMemoryState#KNOWN} value for the given thread

@param thread the thread
@param register the register
@return true if known
Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/pcode/exec/trace/data/DefaultPcodeTraceRegistersAccess.java