I have observed that minor cpu for x86 does not lookup for predictions from branch prediction for control instructions. In minor cpu branch predictor is called at fetch2 stage, and I observed that for x86, in fetch2.cc file, inside the function "Fetch2::predictBranch(MinorDynInstPtr inst, BranchData &branch)", the condition
if (inst->staticInst->isControl() || inst->staticInst->isSyscall()) never gets true for control instructions, probably because the isControl flag is set after decomposition of insts into uops. Saying that I am not very familiar with minor cpu code, so I am not sure if I am missing something. But, I have tested different benchmarks with x86 minor cpu and the stats do not show branch pred lookups. I wonder if someone had similar experience ?
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