3 ms·

Is it the right default? If the vast majority of branches are predictable, then without PGO a branch would be the right choice, no? If they're gonna make this

• pclmulqdq 4y ago
  The vast majority of branches don't fit in the branch predictor, so it is taking no more than a naive guess about them. If you tell LLVM that the branch is likely or unlikely, they shouldn't use a CMOV, and should instead lay out the code so that the naive branch predictor is correct most of the time. Otherwise, the CMOV actually is likely to be beneficial.