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by gpderetta 1073 days ago
In principle is perfectly possible to speculatively execute cmov (and viceversa to change jump-over-one-instruction into conditional execution).

But Intel historically didn't do it as programs tend to use cmov when the condition is unpredictable , so there was little reason to optimize it.

After Spectre, I believe intel has given an architectural guarantee that cmov is never speculated so it can be used as part of speculation attack prevention.