disabling BP has no impact in case of CPU (x86)

[FanosLab]

Hello,
In running few experiments using the BP, I came to an issue where whether we disable BP or not, it does not have any impact on the results.
Looking into the issue, I found that in the frontend_c::predict_bpu function, the BP disabled path has no impact in case of CPU (I am also not very sure how it works on the GPU case):
if (*m_simBase->m_knobs->KNOB_USE_BRANCH_PREDICTION) { // do nothing } // no branch prediction else { // GPU : stall on branch policy, stop fetching if (m_ptx_sim && *m_simBase->m_knobs->KNOB_MT_NO_FETCH_BR) { set_br_wait(uop->m_thread_id); mispredicted = false; } }

My understanding from the flow that is should return mispredicted = true if BP was disabled?
Although semantically disabling BP is not the same as misprediction but this is the closest I can get form the code?
right now simply disabling BP has no impact.

In the meantime, I did something like:
if (*m_simBase->m_knobs->KNOB_USE_BRANCH_PREDICTION) { // do nothing } // no branch prediction else { // GPU : stall on branch policy, stop fetching if (m_ptx_sim && *m_simBase->m_knobs->KNOB_MT_NO_FETCH_BR) { set_br_wait(uop->m_thread_id); mispredicted = false; } else { //CPU x86 path should return misprediction in case that bp is disabled! mispredicted = true; } }
Not sure if this is what originally the code intended or not.

Mohamed