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It appears so. https://developer.arm.com/documentation/102374/0101/Program-flow---conditional-select-instructions https://developer.arm.com/documentation/102374
by ludiludi 3y ago
It appears so. https://developer.arm.com/documentation/102374/0101/Program-flow---conditional-select-instructions https://developer.arm.com/documentation/102374/0101/Program-...
"So far, we have seen examples that use branches to handle decisions. The A64 instruction set also provides conditional select instructions. In many cases, these instructions can be used as an alternative to branches."
Seems CSEL is not a branch.
- masklinn 3y agoCSEL is a conditional move, they’re usually used to avoid branches (and branch predication) entirely. Here it turns out to be a very bad choice, because it creates unnecessary data dependencies. But a cmov would be a fine choice if the branch was impossible to predict (e.g. if the input was random, well even then I’d expect the limit to mostly creep up so it should be predicated as mostly cold).