I asked the same thing a while ago.
They published a paper with the answer
https://millcomputing.com/blog/wp-content/uploads/2018/01/Spectre.03.pdf
see the section called “Software and compiler speculation”
Their answer seems to be a loadtr operation, that will only perform the load if the predicate is met, avoiding branching.
When I asked, they said they were still trying to decide if there was a better way.
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This reply was modified 6 years ago by
goldbug.